FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Roberts Red GTA on July 18, 2025, 08:28:49 AM
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Hello. Trying to decide on what to do with the 428 SCJ engine in the '69 Cobra.
Here is what I know:
Compression is good in all cylinders except #4 which is 150. I determined it is a leaky exhaust valve.
Leak down test revealed very good results with less than 10% loss at 80PSI on all except 4 which is about 15%
Main journals .010 cut. Plastic guage says .0015 clearance. Appearance is perfect smooth and polished.
Rod journals .020 cut. A little scratched but not excessive. Journal looks perfect. Plastic guage says .002 clearance.
Engine has been bored over .040. Has 2287P pistons.
Heads and intake are stock CJ.
The reason I dug into this is that I had no prior knowledge of the car before I bought it 2 weeks ago.
Had an intake manifold lead which leaked coolant into the oil. I checked the life on the hydraulic lifters as exactly factory CJ.
What would you do going forward? Want a dependable, good running car. More power is always good. Concerned about the .040 bore. Willing to put $ into this, but don't need a 550 HP engine. 4 Speed trans with 3:50 gears which I inted to change to 3.91.
Any thoughts are welcome.
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If your worried about the .040 over and have a leaking valve, pull both heads and get a sonic test done on the cylinders and get back to us on the results.
What heads are you using?
You can put in .001 oversize MB, I think the rods will be ok.
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Hello. Trying to decide on what to do with the 428 SCJ engine in the '69 Cobra.
Here is what I know:
Compression is good in all cylinders except #4 which is 150. I determined it is a leaky exhaust valve.
Leak down test revealed very good results with less than 10% loss at 80PSI on all except 4 which is about 15%
Main journals .010 cut. Plastic guage says .0015 clearance. Appearance is perfect smooth and polished.
Rod journals .020 cut. A little scratched but not excessive. Journal looks perfect. Plastic gauge says .002 clearance.
Engine has been bored over .040. Has 2287P pistons.
Heads and intake are stock CJ.
The reason I dug into this is that I had no prior knowledge of the car before I bought it 2 weeks ago.
Had an intake manifold lead which leaked coolant into the oil. I checked the life on the hydraulic lifters as exactly factory CJ.
What would you do going forward? Want a dependable, good running car. More power is always good. Concerned about the .040 bore. Willing to put $ into this, but don't need a 550 HP engine. 4 Speed trans with 3:50 gears which I inted to change to 3.91.
Any thoughts are welcome.
There are a few of us who do concours or near concours builds for owners like you. I would look up Anghels Restorations and look around to see how far you are from original. If you are very close, nothing wrong with going that way, in fact, if you have all the CJ bits, especially things like fittings and PCV setup, carb, etc, you probably should restore it. If you aren't, you get to choose to try go that way or go with a slight hot rod.
As far as what you see, it would be best to have the block checked for taper and square. If it was recently rebuilt, has straight cylinders, likely a square deck, torque plate clean up, replace some push in oil plugs with NPT, and maybe get away with just a re-ring, but it depends what you find. A c-scratch block is "usually" better than others, but should sonic check, then we can get pistons at even .005 larger and just torque plate hone to save cylinder wall.
The crank should be measured more accurately than Plastigauge, but depending on taper, runout and clearance likely reusable
As far as improving, a hydraulic roller cam is always good, adds about 1500 to the build as you build the heads too, best to do some work to the heads to get a good valve spring. However, I really like NOT using aftermarket rockers on a milder one with stock valve covers. End stands, hardened shafts, good hyd rockers keep things light, roomy and last forever. FWIW last all-iron concours 428 hyd roller I did was 485 HP and pump gas / vacuum brakes, it had a little money in it, but won it's class in Lime Rock too, so it looked and acted very stock
https://www.youtube.com/watch?v=mtgO0UFeXIA
If staying flat tappet, if you can determine the cam now, some bluprinting to get things right, degreeing the cam, and a few other tricks can make them run well too.
In the end, think hard what you want the car to be, then find someone who can help you find the target. Welcome to the forum
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x2 -my427- but add has seen some use how hard always ????- mag crank store the rods -- i know they are used over many builds-- i have been running fe iron for 60 years now --orgional rods may be ok - at min. check the web about 1-1/2 inch below pin some rods you may damn near see through-- over all the years a friend had a new factory side oiler short block --rod broke at about first time at around 3500 rpm almost no material in web- i had 390 do the same thing 2500/3000 on interstate same thing rod just no good also they have a life cycle-- store for a numbers guy but do not possibly destroy a lot of good parts/work on a bad rod-- if you dont have a egg on the footfeed - use deeper front sump pan or accumlator or extra qt. at min and windage screen not flat tray type-- good times w/fe-- john-oldiron
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.040 over isn't a concern in my opinion, a good 428 block will handle .060 over despite what you may have read on the internet. Your leakdown checks don't sound too bad either, and it won't lose a lot of power with a leaky exhaust valve. You could run it as-is for a while if you didn't want to go through a major teardown. Standard hot rod stuff, intake, carb, headers and cam will pick you up a lot.
By the way, my 69 Cobra has a .060 over 427 block, made up to 675 HP as a 492" stroker years ago when I did all my intake testing, and still runs fine today at the 600 HP level. It has a Performer RPM intake, FPA headers, a Holley 1000 HP carb, and a pretty stout solid roller cam. If you went with a hydraulic roller cam and maybe a 750 double pumper carb, you could easily get to 500+ HP.
In short, my advice is run it; don't tear it down unless you have to.
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Pull the heads and get the valves touched up to fix #4 then drive the wheels off of it and enjoy it
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We, (I), need pics of machine. Is it a Formal Roof or FB?
You are in the right place being on this forum.
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Here are some photos. I don't have photos of the cylinders yet, but they have the 2287P pistons .040 over. I mic'd the bore and came up with .006 cylinder to piston. I know plastic gauge isn't real reliable, but the rods were .020 larger with .0025 clearance. The crank is .010 under with .0015 clearance.
Add'l it looks like the CJ heads have hardened seats? When I removed a valve there was no evidence of any port work.
Here are some photos I have.
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more photos
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The '69 Cobra.
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I had a red formal roof Torino GT CJ car. Love the look and ride quality was excellent too. I would rebuild the heads and carry on for now.
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Thanks. I have come to the decision to replace the rod bearings. Crankshaft looks excellent. A little tight at .0015 clearance. Still thinking of the edelbrock heads for weight savings and detonation concerns. The camshaft is stock CJ and the dial indicator says it is exactly to specs on lobe lift. At .040 on the bore and the good leakdown results before removing the heads, I will leave the engine in and just deal with the top end.
Brent Lykins mentioned that a cam change could net more hp. I would be willing to do roller hydraulic, etc.
Not sure yet here. With a .040 bore and old style forged pistons, don't know how durable the lower end would be making another 100 HP as I am also looking at headers instead of the CJ exhaust manifold.
Not sure. But I definitely want nicer drivability.
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It's always a slippery slop when modifying a engine but, a few quick things you could do is change out the intake, heads and water pump, for aluminum. That will net you at least 120 lb less weight and give you enough hp to be very noticeable with the header change. Head bolts will need to be replaced, too.
I wouldn't worry about the pistons. Those old, forged pistons are very tough. Those are the things I would do, in the car, with good compression but, if it's out, just open your wallet and do a complete rebuild, including honing, decking, modern pistons and a roller cam.
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Thanks. I have come to the decision to replace the rod bearings. Crankshaft looks excellent. A little tight at .0015 clearance. Still thinking of the edelbrock heads for weight savings and detonation concerns. The camshaft is stock CJ and the dial indicator says it is exactly to specs on lobe lift. At .040 on the bore and the good leakdown results before removing the heads, I will leave the engine in and just deal with the top end.
Brent Lykins mentioned that a cam change could net more hp. I would be willing to do roller hydraulic, etc.
Not sure yet here. With a .040 bore and old style forged pistons, don't know how durable the lower end would be making another 100 HP as I am also looking at headers instead of the CJ exhaust manifold.
Not sure. But I definitely want nicer drivability.
If talking to Brent, he will steer you right, but I'll throw my opinion based on what I would do if you wandered into the shop.
1 - Headers and a modern exhaust with crossover, be sure to use ceramic coated headers in a unibody to control heat
2 - Recurve the distributor based on what you end up with for parts
3 - I'd not bother with Edelbrocks, they save weight but don't perform much better than a CJ head. You could do a modern multi-angle job and 11/32 valve on what you have and do better (minus the weight savings). I also do not consider an Edelbrock being any better for detonation for a properly tuned car with the right parts. TFS with a small modern chamber, maybe, but would have to look close at valve clearance
4 - I'd absolutely go with a custom hyd roller, it will be your biggest gain beyond the headers.
5 - The CJ intake works well, but really heavy. I like a Performer RPM intake unless it's a shaker or Ram Air car, then you need to look at carb position.
A CJ with a modern cam, built to match use, and a nice vacuum secondary, CJ or aftermarket, will be a strong runner and if done well, extremely drivable.
As far as your clearances, bearing manufacturers vary noticeably, I tend to see FM 125M the loosest, but you could also try a King or Clevite (I use Clevite the most due to consistency). Don't be afraid to deburr the bearing either. I'd really like to see you at .0025-.003, especially on a used block and crank.
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First of all, thanks to all for the replies!
My goal is 450 or so HP. More better, but not at the cost of drivability.
What roller cam/lifters? The long term goal is power brakes and 3.91 alxe ratio. The car has a 4 speed transmission.
I have a set of Hooker supercomps ceramic on my '66 gta. And, though difficult to get in there, seal excellent. The negative is how low they hang. I understand FPAs are better at tucked under. Dougs? I would love a sugg here.
The valves look good. I removed the exhaust valve to inspect. Looks completely stock. Old of course.
The RPM intake for sure. Thinking of a 780 VS Holley.
The car still has the stock distributor. Amazing.
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Keep the CJ carb. The only basic difference is the primary boosters and they help with overall mileage and driveablity. The cfm reduction comes from the boosters being larger.
The Edel, overall is a much better head than the CJ head. The intake flows about 10 cfm better than the CJ but, the Edel, doesn't have the 2 ports, that are restricted because they have protrusions in them like the factory heads and the ex flows much better.
TFC heads flow much better BUT, while some say that the piston valve reliefs can work, no one will guarantee it. Basically it should not work, because the valve location is different and the valve is .100 larger. I think any that get away with it, do so, because the piston isn't high enough on overlap.
So, if you get a build done and your valves don't have enough clearance, it's another tear down and $1000+ in pistons and rings.
BTW, is the engine still in the car?
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First of all, thanks to all for the replies!
My goal is 450 or so HP. More better, but not at the cost of drivability.
What roller cam/lifters? The long term goal is power brakes and 3.91 alxe ratio. The car has a 4 speed transmission.
I have a set of Hooker supercomps ceramic on my '66 gta. And, though difficult to get in there, seal excellent. The negative is how low they hang. I understand FPAs are better at tucked under. Dougs? I would love a sugg here.
The valves look good. I removed the exhaust valve to inspect. Looks completely stock. Old of course.
The RPM intake for sure. Thinking of a 780 VS Holley.
The car still has the stock distributor. Amazing.
Your goals are easy to do. If you have a relationship with Brent, he'll cam you properly. I do it too, but you mentioned talking to him and I'd stay stick with him if you are talking. He, as would I, will ask you for some careful data to spec a cam, but it's worth it. Those that run the CJ circles have to solve the issue all the time, power brakes, parade-driving when needed, and haul the mail when asked. Pretty easy combo and likely could sneak a bit more power out when you add the RPM intake.
Cam brand is less important than understanding lobe design. I have had great luck with Morel lifters, but spring setup is critical for any hyd roller.
Some plusses with Edelbrock heads, weight mostly, but significant minuses too, heavier valve train, spring package isn't great and wrong for an FE hyd roller, valve job and valves are nothing special for flow, guides can be tight. If you sold your CJ heads, you could certainly modify new Edels to outperform CJs and save weight, but to out perform a set of CJ's prepped properly, it'll mean a modern valve job and spring package, adding to the cost, so an order from Summit won't cut it.
FYI, in either head, prepped properly means valve seat angles and valves that work with those heads, in the CJ I would go lighter (and new/safe) 11/32 valves, bronze guides, and a matching spring package with spring cups and Viton seals, cut the deck and exhaust surface. With Edels I'd likely do a guide clearance check, work the seat and valve, and just make sure the spring package could handle the heavy 3/8 valve, they also tend to come in big, but regardless, in either head you need to complete them and calculate compression to get all you can out of the cam.
In the end, in some ways it makes the C8OE-N not too expensive and better than Edels out of the box (no assuming port work, just prep).
Frank isn't wrong about the TFS, depends on valve drop and available space, but my point wasn't to go with TFS, it was that the chamber and port of an Edelbrock ain't all that. The TFS is much better, but I probably wouldn't bother unless you want to make even more power and willing to go inside.
Super Comps are excellent, and in most cases FPA headers are too, and slightly better for power. My last set of FPAs on a customer's Torino needed a little adjustment at the collectors. Basically they sat a little wide and crowded the frame, easy fix though, long pipe in the header it self and a shove, they fit perfect.
I also like the CJ carb, last all iron CJ I did was 486 HP on an 850, 476 on a stock CJ carb (iron head and CJ intake, no spacer, 229 duration cam with high vacuum and drivability). However, if going new I would use a QFT HR780VS over a Holley, doesn't look stock but a great carb. We just installed one on a customer's 66 428PI in a real police car (395-ish HP) and it's very happy and you get electric choke
The stock distributor is a good one, generally, I send them to Rockhouse Racing to be restored and while he is at it, add a steel gear for the HR cam. He can do what they call the Tasca curve, which almost always works well with a stock head or the Edelbrock, certainly helps drivability and acceleration.
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Keep the CJ carb. The only basic difference is the primary boosters and they help with overall mileage and driveablity. The cfm reduction comes from the boosters being larger.
The Edel, overall is a much better head than the CJ head. The intake flows about 10 cfm better than the CJ but, the Edel, doesn't have the 2 ports, that are restricted because they have protrusions in them like the factory heads and the ex flows much better.
TFC heads flow much better BUT, while some say that the piston valve reliefs can work, no one will guarantee it. Basically it should not work, because the valve location is different and the valve is .100 larger. I think any that get away with it, do so, because the piston isn't high enough on overlap.
So, if you get a build done and your valves don't have enough clearance, it's another tear down and $1000+ in pistons and rings.
BTW, is the engine still in the car?
Engine still in car. The car had a really expensive paint job and during this period the owner died. Tons of interior and exterior parts missing. I took a chance buying the car because of it being an actual R code, though not originally a SCJ.
I took #4 main cap off yesterday and confirmed it, too, looked excellent. According to the plasticgauge I used, It is about .002 clearance. I am ordering a set of rod bearings today along with some gaskets.
I don't know who to take the heads to if I decide to keep. I still like the aluminum ones, though I realize they are not Barry's heads (which I put on the '66 and like them a lot).
Also like the idea of aluminum for weight purposes. At 70 removing the cast iron intake myself was a job.
Aluminum water pump, heads and intake will lighten the heavy front end up a bit for sure.
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First of all, thanks to all for the replies!
My goal is 450 or so HP. More better, but not at the cost of drivability.
What roller cam/lifters? The long term goal is power brakes and 3.91 alxe ratio. The car has a 4 speed transmission.
I have a set of Hooker supercomps ceramic on my '66 gta. And, though difficult to get in there, seal excellent. The negative is how low they hang. I understand FPAs are better at tucked under. Dougs? I would love a sugg here.
The valves look good. I removed the exhaust valve to inspect. Looks completely stock. Old of course.
The RPM intake for sure. Thinking of a 780 VS Holley.
The car still has the stock distributor. Amazing.
Your goals are easy to do. If you have a relationship with Brent, he'll cam you properly. I do it too, but you mentioned talking to him and I'd stay stick with him if you are talking. He, as would I, will ask you for some careful data to spec a cam, but it's worth it. Those that run the CJ circles have to solve the issue all the time, power brakes, parade-driving when needed, and haul the mail when asked. Pretty easy combo and likely could sneak a bit more power out when you add the RPM intake.
Cam brand is less important than understanding lobe design. I have had great luck with Morel lifters, but spring setup is critical for any hyd roller.
Some plusses with Edelbrock heads, weight mostly, but significant minuses too, heavier valve train, spring package isn't great and wrong for an FE hyd roller, valve job and valves are nothing special for flow, guides can be tight. If you sold your CJ heads, you could certainly modify new Edels to outperform CJs and save weight, but to out perform a set of CJ's prepped properly, it'll mean a modern valve job and spring package, adding to the cost, so an order from Summit won't cut it.
FYI, in either head, prepped properly means valve seat angles and valves that work with those heads, in the CJ I would go lighter (and new/safe) 11/32 valves, bronze guides, and a matching spring package with spring cups and Viton seals, cut the deck and exhaust surface. With Edels I'd likely do a guide clearance check, work the seat and valve, and just make sure the spring package could handle the heavy 3/8 valve, they also tend to come in big, but regardless, in either head you need to complete them and calculate compression to get all you can out of the cam.
In the end, in some ways it makes the C8OE-N not too expensive and better than Edels out of the box (no assuming port work, just prep).
Frank isn't wrong about the TFS, depends on valve drop and available space, but my point wasn't to go with TFS, it was that the chamber and port of an Edelbrock ain't all that. The TFS is much better, but I probably wouldn't bother unless you want to make even more power and willing to go inside.
Super Comps are excellent, and in most cases FPA headers are too, and slightly better for power. My last set of FPAs on a customer's Torino needed a little adjustment at the collectors. Basically they sat a little wide and crowded the frame, easy fix though, long pipe in the header it self and a shove, they fit perfect.
I also like the CJ carb, last all iron CJ I did was 486 HP on an 850, 476 on a stock CJ carb (iron head and CJ intake, no spacer, 229 duration cam with high vacuum and drivability). However, if going new I would use a QFT HR780VS over a Holley, doesn't look stock but a great carb. We just installed one on a customer's 66 428PI in a real police car (395-ish HP) and it's very happy and you get electric choke
The stock distributor is a good one, generally, I send them to Rockhouse Racing to be restored and while he is at it, add a steel gear for the HR cam. He can do what they call the Tasca curve, which almost always works well with a stock head or the Edelbrock, certainly helps drivability and acceleration.
I have the quickfuel carb on the '66 stroker and it is a good one along with Barry's heads which are great. I am still leaning to the Edel head for weight along with intake and water pump. At 70 taking that cast iron intake off was almost undoable alone.
And, I have only received a short email from Brent saying that a camshaft would yield 425HP with the rest left alone. So, need a sugg on camshaft.
Gear 3.91, 4 speed. Sugg?
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There are some Howards cams that could work, but they leave quite a bit of power on the table. A custom cam is the only way to fly.
The right selection will take some measuring of the heads, deck height, compression calculation, discuss intended use, desired fuel, and finalizing all the parts, but aside from needing to know the resulting compression with Edelbrocks and the gasket choice...it's not a tough one to solve.
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First of all, thanks to all for the replies!
My goal is 450 or so HP. More better, but not at the cost of drivability.
What roller cam/lifters? The long term goal is power brakes and 3.91 alxe ratio. The car has a 4 speed transmission.
I have a set of Hooker supercomps ceramic on my '66 gta. And, though difficult to get in there, seal excellent. The negative is how low they hang. I understand FPAs are better at tucked under. Dougs? I would love a sugg here.
The valves look good. I removed the exhaust valve to inspect. Looks completely stock. Old of course.
The RPM intake for sure. Thinking of a 780 VS Holley.
The car still has the stock distributor. Amazing.
Your goals are easy to do. If you have a relationship with Brent, he'll cam you properly. I do it too, but you mentioned talking to him and I'd stay stick with him if you are talking. He, as would I, will ask you for some careful data to spec a cam, but it's worth it. Those that run the CJ circles have to solve the issue all the time, power brakes, parade-driving when needed, and haul the mail when asked. Pretty easy combo and likely could sneak a bit more power out when you add the RPM intake.
Cam brand is less important than understanding lobe design. I have had great luck with Morel lifters, but spring setup is critical for any hyd roller.
Some plusses with Edelbrock heads, weight mostly, but significant minuses too, heavier valve train, spring package isn't great and wrong for an FE hyd roller, valve job and valves are nothing special for flow, guides can be tight. If you sold your CJ heads, you could certainly modify new Edels to outperform CJs and save weight, but to out perform a set of CJ's prepped properly, it'll mean a modern valve job and spring package, adding to the cost, so an order from Summit won't cut it.
FYI, in either head, prepped properly means valve seat angles and valves that work with those heads, in the CJ I would go lighter (and new/safe) 11/32 valves, bronze guides, and a matching spring package with spring cups and Viton seals, cut the deck and exhaust surface. With Edels I'd likely do a guide clearance check, work the seat and valve, and just make sure the spring package could handle the heavy 3/8 valve, they also tend to come in big, but regardless, in either head you need to complete them and calculate compression to get all you can out of the cam.
In the end, in some ways it makes the C8OE-N not too expensive and better than Edels out of the box (no assuming port work, just prep).
Frank isn't wrong about the TFS, depends on valve drop and available space, but my point wasn't to go with TFS, it was that the chamber and port of an Edelbrock ain't all that. The TFS is much better, but I probably wouldn't bother unless you want to make even more power and willing to go inside.
Super Comps are excellent, and in most cases FPA headers are too, and slightly better for power. My last set of FPAs on a customer's Torino needed a little adjustment at the collectors. Basically they sat a little wide and crowded the frame, easy fix though, long pipe in the header it self and a shove, they fit perfect.
I also like the CJ carb, last all iron CJ I did was 486 HP on an 850, 476 on a stock CJ carb (iron head and CJ intake, no spacer, 229 duration cam with high vacuum and drivability). However, if going new I would use a QFT HR780VS over a Holley, doesn't look stock but a great carb. We just installed one on a customer's 66 428PI in a real police car (395-ish HP) and it's very happy and you get electric choke
The stock distributor is a good one, generally, I send them to Rockhouse Racing to be restored and while he is at it, add a steel gear for the HR cam. He can do what they call the Tasca curve, which almost always works well with a stock head or the Edelbrock, certainly helps drivability and acceleration.
I have the quickfuel carb on the '66 stroker and it is a good one along with Barry's heads which are great. I am still leaning to the Edel head for weight along with intake and water pump. At 70 taking that cast iron intake off was almost undoable alone.
And, I have only received a short email from Brent saying that a camshaft would yield 425HP with the rest left alone. So, need a sugg on camshaft.
Gear 3.91, 4 speed. Sugg?
When you figure out which way you want to go, I can look at the specs for you. Everything changes everything, so if you change cylinder heads, the cam specs change.
I've made an easy 425-430 hp with all stock CJ components and have made about 450-460 with a 428, C6AE-R heads, BT PI intake, etc.
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Just wanted everyone to know how much I appreciated your help.
In the end Barry was only 45 minutes away. I had contacted him abt a week ago and he spec'd a complete rebuild. So, I went over to his place and he confirmed that the bottom end looked pretty good. Told me that the bearings were looking good.
I respect his help and decided on Trick Flow heads, HS rockers, hyd roller cam and lifters. Similar to the build I did on my '66 GTA. I wanted a milder cam, but am sold on roller assby.
Thanks for all the help everyone.
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That paint is jumping! Nice