428 rod and piston upgrade only vs complete stroker kit

[KeiserMustang]

Hey guys, been out of the game for a long time (raising kids, work commitments, etc.)  Threw a Hail Mary back in August and decided to pull my 428 off the stand after more than 10 years and put it back in the Mustang for the Cobra Jet reunion at the NMCA race in Norwalk.

This is a long story....

My dad and I put this engine together back in 2000 on a young man's budget.  428 'A' block, stock 1U crank, C6AE-B rods, TRW forged stock replacement pistons.  Block was bored .030", rotating assembly balanced, ARP bolts throughout.  At that time, I put on a set of Edelbrock Performer RPM heads and intake, pretty much out of the box (maybe a gasket match).  Cam was/is a Comp solid, flat tappet, 242/252 @ .050 and .564/.590 lift, "shell" lifters and Harland Sharp rockers.

We managed to get the car (68 Mustang fastback) to run consistent 11. teens @ 118 mph with a JPT C4 trans and converter, 4.56 gear/29" tire. I ran the car quite a bit up until 2008 when I made a tough decision to sell it.  I did however keep the drive train.

Fast forward to 2016 when I was fortunate to be able to buy the car back.  It returned to me with a 410 CI small block, Joel's on Joy C4, 4.10 gears and Mickey Thompson ET Radial Pro tires (28-ish dia).  I ran this combination in NMCA Nostalgia Muscle car on the 10.50 index for 4 races in 2016 and just once in 2017.

So back to the 428...
I robbed the heads and rockers off this engine years ago and the intake was sold along the way, but the short block stayed together under cover in the shop.   Back in August, I simply cleaned it up, put on a set of the new Trick Flow heads and Intake, Comp Ultra Gold rockers, and back in it went with the original JPT trans and converter.  This time I stayed with the 4.10's and radial tires.  Then off to the reunion! 

This thing SHOCKED me and ran 4 consecutive passes between 10.50 and 10.54 @ 126+ mph.  That's 5 tenths and 8 mph faster, 18 years later with the new heads and intake (the car is also about 200 lbs heavier than it was back then).  On my way up for R2 qualifying the oil pressure started to go away.  Cutting the oil filter apart we found the oil had lot's of "glitter" but no major debris.  We winched it in the trailer and enjoyed the rest of the weekend as spectators.

I will assume for now that it has spun a bearing but will tear it down after Christmas to confirm.  So I'm contemplating where to go from here.  The combination as-is seems to be magic.  I just want to get it back together and reliable so we can get back to racing.  However, based on the weight of the car (3400 lbs), ET, & mph I'm figuring the engine was making around 530-550 hp.  I'm not comfortable at that level with the stock rods and pistons.

So to my FE friends I say, where to go from here?  From what I've seen, a decent set of rods and pistons is going to be in the neighborhood of $1,500...plus balancing, rings, bearings, etc. would get me up to about $1,950.  I've seen complete rotating assemblies ranging from $1,700 to $2,300.  I'm figuring the $$ for the rest of the machining is going to be the same either way. If I went the stroker route with a 4.25 stroke, flat top piston...compression is going to jump from 10.6 ish to 11.8 and displacement increase to 462.  I would think it's going to be hard NOT to make considerably more horsepower.  If it's legitimately making 550-ish HP now, even if I leave the small cam in it, the jump in compression and CU IN  would surely push it up to 600 or more I would think? As crazy as it sounds, I'm really not sure I want to do that...?

It's easy to get sucked in to going for more, but is it worth it in this case?  Will the extra power from the stroker setup end up costing me alot more in the long run? I'm thinking I'd at least have to have a different flexplate (internal balance vs. external), re-stalled or new converter, gears, etc. And will the block survive there??

But is the stock crank and block even safe for the 550 HP it's making now?  And did I mention the combination as is was netting 7000 RPM through the lights...

[plovett]

I think I would be comfortable at that hp level with stock rods and pistons.  Your bearings and metal in the oil are a separate issue, IMO. 

What rpm are you running?

paulie

[KeiserMustang]

Shifting around 6400...ran through the top end at 7000.  But there again, only 4 passes on the "new" combination.  Never dreamed it would pick up 8 mph so the 7000 rpm was a surprise.

[WerbyFord]

Shifting around 6400...ran through the top end at 7000.  But there again, only 4 passes on the "new" combination.  Never dreamed it would pick up 8 mph so the 7000 rpm was a surprise.

More detail!!!
This is a fascinating combo for the Gonkulator.
Car weight w /driver? (My guess 3470 down the track?)
Open headers of course?
Carb?
Fan?
Electric water pump?
(Fan & belts can affect trap speed quite a bit)
Any 60ft times?
Weather during these runs? (Edel vs TFS)

The Gonkulator is only gaining 5-6 mph between the Edel and TFS combo, was there a tailwind at FERR? 10mph tailwind would add 2mph to trap speed? In any case that 8mph is a HUGE gain. Speaks highly of those heads.

As far as the stroker and 11.8 CR, the Gonkulator says that's about 0.3 sec and 3mph better than what you have now.

I gotta make one of these FERR some year!

[Rory428]

Concerning stock 428 blocks, cranks and rods, I have hundreds of low 10 second 1/4 mile runs, and a couple of high 9s, on stock cast factory 1U crankshafts, with no issues ever. With stock 428 blocks, I have had a few split cylinder walls, and and 1 block that split the main webbing between the main bearing bores and cam bearings . I also used to run resized C7AE-B rods , but not anymore after a few too many failures. AS for the long stroker cranks, at least around here, I have seen more quick naturally aspirated  FEs  (mid 10s and quicker) at the dragstrip , with factory stroke cranks than strokers. Obviously a serious big inch FE can be built, but many seem to be milder street cruiser type stroker engines.

[KeiserMustang]

In the first eight years that we ran the car, we ran in all weather conditions at lots of different tracks around the Midwest. It had at one point ran a best ever 10.90 at 120 miles per hour. But that was at a race weight of 3200 lb with me in it and7the best air we'd ever run in. After adding some ballast to get consistent 60-foot times in the high 1.4 range, the car was consistent at low 11 second ET's. The weather at Norwalk for the 50th anniversary of the Cobra Jet was an adjusted gross altitude of around 2,000 feet. No significant tail wind to speak of. So it was at least a reasonable comparison to the way the car ran in the early years. 60 ft times with the TFS setup were also 1.44-1.46. It's a purpose built class car, open headers, electric water pump, and last passes were at a race weight of 3,400 lbs. Lot's of pictures of the car and the build on Instagram @ keisers_garage

[My427stang]

Did you calculate compression before and after?

Certainly gains in airflow, but you also have a significantly smaller chamber, just bench racing on reason for the HP increase.

My opinion on stroker versus rebuild. 

- With a rebuild with better rods, better pistons, thinner rings, etc. you will likely gain little power and quite a bit of reliability.  Pistons will be a little lighter, rings will have much less drag, and you can pick a compression ratio that suits your use (which could be even higher depending on where you are now).  Keep in mind a fresh bore with torque plates, potentially square decking all add cost, but are needed to take advantage of the small gains in power.  Without a cam change though, I would expect it to act pretty much as it does now, personality wise.

- With a stroker, the personality can/will change, all the good parts and machine work with the same cam/compression, etc, will likely put suspension to the test at launch.  Torque will be higher, 1-2 shift points lower, and depending on build need a regear.  Certainly, if traction is marginal, you will have to launch differently or work on suspension.  However, it does give you the opportunity to recam and make significantly more power than you would with the 428, but it's significantly more money when you get the car ready for it.  That being said, I watched one of Blair's 482 builds, click off sub 10s all day in Georgia, and it looked like the driver was just taking a Sunday drive.  All of our guys are doing those types of builds, but I can attest to the combination of suspension, tuning and build to that car and how easy it was for him to go fast.

My hunch is that IF you go inside, go deep.  Map the wall thickness, square the block, and let the budget and timeline steer you.  IMHO you are fast and reliable now, good place to be

[KeiserMustang]

I did try to calculate the compression ratio difference.  Using 76cc for the chamber volume on the Edelbrock heads and a .040" head gasket (Felpro's) and 72cc for the TFS and .027" (switched to Cometics), I figured the increase in compression at around .5 - .6 (10.2:1 to 10.8:1)

I'm pretty confident in the suspension/chassis setup.  I've done more work over the years to improve traction and 60' consistency than anything else.  The car hooks well and caries a nice wheelie all the time.

When the block was prepped 20 years ago, my local machine shop didn't have torque plates for and FE, so the hone was done without them.  It's never been decked either.  In the current configuration, the pistons are .015" in the hole.

There's another, rather embarrassing problem too...I know it has miss-matched main caps 

By some crazy chance, the "Chevy" shop where the machine work was done happened to have 2 FE blocks at the same time.  When I brought mine home my dad started the assembly.  Right out of the gate he asked me why I didn't number the main caps (he taught me that when I was a kid).  I assured him that I had and told him to look for center punch marks on the caps...1 dot, 2 dots, 3...
He said he didn't see any.  I thought I'd lost my mind.  Anyway, he put the caps on and torqued them down and the crank locked up.  He moved them around and got it to turn but told me for sure the it needed to go back and be line honed.  I was in a big hurry and decided to plasti-gauge the clearances and let it run...OMG this sounds terrible.  It ran 8 years that way.  Before I put it together back in August I pulled a couple connecting rod caps and the bearings looked great.  I pulled the #2 and #4 main caps...not so good.  Both showed quite a bit of wear and #4 was worn on one side.  Hence the reason I believe the loss of oil pressure and metal in the oil is a failed bearing.

I know I shouldn't have run it that way (either time), but it was important to make it to the 50th and a complete rebuild wasn't in the cards.

And I hadn't lost my mind on the caps either...believe it or not, that other FE block at the machine shop when mine was there...yeah, it got left there for years and the guy who left it there never came back for it.  So years later, I ended up with it...and when I got it home and looked it over...low and behold there were the my main caps, with center punch marks and all!

[My427stang]

I did try to calculate the compression ratio difference.  Using 76cc for the chamber volume on the Edelbrock heads and a .040" head gasket (Felpro's) and 72cc for the TFS and .027" (switched to Cometics), I figured the increase in compression at around .5 - .6 (10.2:1 to 10.8:1)

So I haven't used a set of TFS, but talking to Brent Lykins, he said he has been seeing small chambers on those heads, under 70 ccs, so you are likely closer to a full point of compression.

[WerbyFord]

Great story on the main caps.
That compression & quench diff explains about another 1mph so the Gonkulator is now seeing about 6-7 mph, Edel setup vs TFS setup, about 60 ftlb and 100 hp better.

Thanks for the data, direct comparisons are rare on the dyno but even more rare on the strip.

[BigBlueIron]

Wow funny how some things work out. So are you going to put original numbered caps on this time and run it??

[KeiserMustang]

Lol...no, after more research on blocks and horsepower limitations, I've talked myself into a Pro Gram crossbolt conversion.

[KeiserMustang]

Rotating assembly is a moot point at this juncture. Block is cracked on the #2 main web.

I am officially in the market for a replacement.  Open to any and all options.

Would love some feedback.

[mbrunson427]

Where are you from? You said the midwest?

Might be time for a 445 stroker with those TFS heads? You could likely find a 390 block for pennies on the dollar compared to a good 428 block.

I took a look at your instagram page, Mustang is super nice!

[KeiserMustang]

Thank you. I'm in central Indiana.

I have several 390 blocks. It seems like the combination I have is going to be good for north of 550hp and upwards of 7000 RPM. Any factory block is going to need a lot of work to live there. Wondering if it's just time to make the jump to an aftermarket block?

If I do opt to spend that money on a factory block, is it worth it to be limited to the performance capability of a 445?