427 stroker build

[Dan859]

Hi everyone,
I have a 64 Comet Caliente set up as something like an A/FX.  It has a Mustang II front end, a 457 CID engine (Genesis 427 with 428 crank), TKO transmission, and a MW rear end with 3.91 gears.  The engine specs are:

427 Genesis block
428 crank, offset ground to 4.00 stroke, with 400 Cleveland rods
Venolia forged 10.5 C.R. pistons
Bullet hyd. roller cam and lifters, adv 305/310 duration, 243/254 @ .050, .585 lift
Dove HR heads
Dove HR tunnel wedge intake
Dove HD roller rocker assembly
Holley twin 80457 carbs, 600 cfm each
MSD ignition, 36 total advance, in by 3000 RPM

I had the engine dynoed, it showed 532 HP @ 6000 RPM, and 506 lb ft @ 4500 RPM, with a redline of 6000 RPM.  Since I had the engine built, I've since read that the 400 Cleveland rods aren't really a good idea, so that concerns me.  I also had hoped for 600 HP out of the engine, which I didn't get.  Another issue is that the engine isn't real street friendly at low RPMs.  It runs rough and there's a lot of reversion back into the carbs. 
I should add that this is my first foray into an engine like this.  I've had a 68 Fairlane 390 and a couple 70 429CJ Torinos, but nothing like this.  My goals are to have a street friendly car that develops 600 HP with a 6000-6500 RPM redline.  I want to stick with a hydraulic roller cam because I have to remove the brake master cylinder and vacuum booster in order to remove the valve cover to adjust the valves.
 
My thought at this point is that I should just bite the bullet and rebuild the engine as follows:
Scat 4.25 stroker kit, which will give me 482 CID, keeping about 10.5 CR.
Survival or BBM heads, just a basic cleanup and port matching, with an aftermarket roller valve train.
Dual quad intake, either a BT med riser dual plane, or a Dove MR tunnel wedge, with dual Holley carbs.
Hyd roller cam, with less duration and higher lift than the current cam.

Any thoughts, comments or suggestions would be greatly appreciated.  I'm especially interested in camshaft profile and intake/carb recommendations.
Thanks,
Dan

[BH107]

The experts here will have better specifics, but I think if you are going with a stroker kit and a cam change then the top end should be fine, with the exception of maybe better carbs.

[fastback 427]

I would get the stroker kit for sure, 400 rods are junk. I would think that your dove high risers and tunnel wedge are more than adequate for 600 HP. Its hard to say for sure without flow numbers, but I think your leaving a lot on the table with that cam. I'd guess around .700 lift would add a lot. Also check the header alignment on the head, my dove medium risers have a raised exhaust roof. There's a lot of smart fellers over here, especially for picking a cam.

[My427stang]

I agree, the heads and intake will support 600 hp, they flow about 350-ish with a good valve job, but they will want more lift to do so. I sure wouldnt go down in duration, just get a better grind that has more .050

Keep the top end but freshen it up with a set of beehive or conical springs for a little better valve control, put a 4.25 stroke crank in there and add more cam

I am sure some our builders here can help you with a good grind, but as a WAG I'd be running a bit more .050 duration, probably close to the low 250s, with the added cubes

[jayb]

I'd agree on the additional cubes, but I'd also recommend changing the heads and intake.  I have a set of those Dove high riser heads, and the ports are huge for the amount of flow you get; not a lot of flow velocity in those heads, and the intake is the same way.  If you decide to shoot higher, maybe 700 HP, those heads and intake would be fine, but I think going with a set of ported Survival heads and BT 2X4 intake as you outlined would easily get you 600 HP and make the engine a lot more responsive at lower engine speeds, and a lot more street friendly.  Probably the huge ports and intake runners in the Dove parts contributed to the existing engine's substandard performance.

On the cam, I think you are close but I'd be going up to maybe something around .640 lift and 250-254 @ .050" on the intake lobe.  Good luck on the project, and welcome to the forum - Jay

[CaptCobrajet]

You are suffering from "COMBO".   COMBO is not terminal..........so far we have a 100% recovery rate for Combo.  Jay is right about the volume issue.  The Dove HR intake and heads need about two quarts of Z-spar spread around in various places to get them to come around for what you describe.  There are options.  The better suited the head, the less cam is required.  If you use the right head, and the rest of the engine is good quality, it should make your 600 hp no problem.  My first thought is a BP Pro-Port..........I know the guy that does those, LOL.  The BBM or the Survival would probably get you there without a full-on port job...........but the prep would have to be right for the task.  There is alot of good info on this site from alot of good and knowledgeable folks.  As Jay said, welcome to our small piece of the web here!

[Barry_R]

Concur with the consensus  (might be too many fancy words there...)

But the combination could use some help.  The 400 rods & such are pretty old school but not in a good way, and date back to when we could not get good parts and guys used anything they could find to build a stroker on a budget.  The newer stroker combinations are just way better for less cost - no comparison - do it.

The heads are a maybe type of item.  The cool factor of running a high riser cannot be denied.  Depending on the iteration of the castings they may be anywhere from pretty decent to just usable.  The OEM type port is really tall and narrow - and like Blair said - it cries out for about an inch of filler.  My local guy squeezes his head filler out of an electrical tube that runs on 220.  On the other hand its possible that your heads could have the PIE port - named for Mr. Paquet of Super Stock fame.  That port is radically better, with the fill already applied and more width.

No matter which intake you have, the fill it up comment is good, but I don't know if two quarts will be enough.  But if you just want to drive it, a huge intake can be made to work OK with effort.  It'll never accelerate the car down track like it should,  but it will cruise around pretty well and make power.  I would probably have a pair of 750s on there.

A basic 482 with Survival heads and a normal tunnel wedge or good single four is a +/-600 HP capable piece - we've done several of them at this point.  I just kinda hate tossing so many usable parts out of the mix if we don't need to.

My personal guess might be to first rework the existing package & see what happens.  Stroker kit, shorter duration cam to hang on to some cylinder pressure, and revisit the carbs and heads to see whats going on there.  I'd be willing to bet that you'll find the same or more power and a much friendlier package.

[faulkdaddy]

I'm no expert or FE god but, I do agree with Jay, Blair and Barry. Heads are probably alittle too big for given application , as well as the intake. Since you want to go stroker. Why not go for the 4.375 crank and see if the size of the engine can catch up to the heads and intake combo you already have? Wouldn't that fix some of the lack of bottom end response that is being experienced? I would go alittle bigger on the cam mid 250's intake for .050 and depending on the exhaust around low 260's at .050 with approximately .650" to .675" lift. JMO on the cam though. Again I'm no expert or FE god. But, I bet you could fix alot of what is being experienced here with alot more stroke and not get rid of some pretty good parts. Oh, there would be alot of torque also and the 600 hp thingy would be achieved too.

Bruce Faulkner
SSG U.S. ARMY (RET)

[plovett]

Ah heck, I guess I'll put my 2 cents in.    For sure the engine builder guys know way more than I do, but I just can't keep my mouth shut. 

I would leave the short block alone.  Is it as good and strong as a new 4.25" stroker assembly?  Definitely not.  BUT, the short block is not why you haven't met your power goals.   In my opinion it is the heads, intake, cam, and carbs.  I would replace that stuff and keep your shortblock.  I will admit that I am partial to unusual combinations like you have in your short block, so I am bit biased.  Plus it's all American made which is also cool.

So get better heads and intake.  Well done Proports may be the best choice.  Survival heads would be awesome as well (Okay, BBM, too  ) .  Or even expertly ported plain ole' Edelbrocks would get you there.

The intake is a little harder choice at the 600 hp level in my opinion.  Lots of ways to get there.  Considering the gearing and vehicle weight a ported Victor would work.  But at 600 hp there are "lesser" intakes that can get you there, too.  Even an Edelbrock RPM could do it, though you'd likely lose some top end power.  I think the Blue Thunder 2x4 intake would be fantastic.  And since you could use new carbs, you could move to some nice Holley 750's.

I'd put about 6-8 degrees more cam duration and a little more lift, maybe 0.600-0.625".   The hydraulic cam is a real bottle neck in my opinion.  You want more duration to make more power, but then you'll need to run more rpm, and that gets harder and harder with a hydraulic roller.  You can science-out your valve train with light weight retainers and valves and such and probably get to 6500 rpm or slightly more.  That would probably be enough.  Plus I'm not sure if you have a pump or accumulator for your power brakes?   

I feel like the hydraulic roller is really the focal point of all this.  I realize this contradicts almost everything I've said up to this point, but max cubes from a stroker kit is really your friend if you want to stay with a hydraulic roller cam.  The more cubes you have the lower your rpm will be for a certain power level and the easier it'll be on your valvetrain.  Having a hydraulic roller cam really accentuates this characteristic.

Ah hell,  let me put it this way.

Option 1) If I owned this motor I would get some good Proport or Survival heads, a BT 2x4 intake, and two Holley 750 carbs.  Then I would ditch the power brakes and put in a solid roller with about 252 to 258 degrees duration.  I'd spin it in the 6500-6800 rpm range and hope the rods didn't let go.

Option 2) For someone who wants to keep the power brakes AND the hydraulic roller, a big motor just makes sense.  So you might as well get a stroker kit.  4.25" or even 4.375".   Then put a slightly bigger  hydraulic roller cam in and some Holley 750's.  Then I'd see how that does with your current heads and intake and go from there.  Things is, if you end up replacing the heads and intake, well now you have almost a whole new motor.  Only the block is remaining. 

Option 3) Keep the shortblock, get the good heads and intake, and get a better hydraulic roller cam, but not one with a lot (or any) more duration.  Maybe one specifically picked by one of the engine builder guys.  It might have more lift and just the right duration and other spec's to get you some more power without raising your rpm much.  With good valvetrain parts you might take it to 6500 rpm or less and still make over 600 hp.

semi-coherent ramble officially over!

JMO,

paulie

[blykins]

I would do either one of two things....

1.  Add displacement to help with the current cylinder head port volume.  A big inch motor will suck harder on a fat cylinder head. 

2.  Stick with the current displacement and snag another set of heads.  My 482-490 inch motors with Pond heads or worked Edelbrocks are 575-600 hp engines with small-ish hydraulic roller cams. 

For what you're wanting to do, keeping the rpms down, needing vacuum, etc, etc., either one of those would help, and either is a viable option. 

Once you decide on which way you want to go, that will dictate which camshaft to use. 

[machoneman]

My 2 cents! Think the most economical and easiest way to 'fix' it is to get new heads as noted above and either save the Dove Hi-Risers for a true full bore race engine or sell them. JMO!

[Qikbbstang]

Capt Cobra Jet: Blair I'm stumped if you were serious or simply making a joke on the name of the "extreme"  volume of  "filler" required to reduce the volume of the Dove HR intake and heads.

Z-Spar from what I see is a marine varnish hardly what I'd think is compatible with fuel:air, pulsing and engine heat.  But maybe the Z-Spar works well"

 Re: "need about two quarts of Z-spar spread around in various places to get them to come around'

[CaptCobrajet]

Z-spar "splash zone repair" BB.  A-788..........check it out.  Alot of the "head gurus" repackage the stuff and charge 3X the price, but I get it from Go2marine.com.  It is the best filler for the induction side, by far.

[Drew Pojedinec]

On my tugboat, we keep 5-6 gallons of the stuff around.
We've actually poked a hole in the boat, had a diver stuff some SplashZone over the hole from the outside and went back to work for another 2 years.

[TomP]

This is encouraging , I won't need to wait for the rain to stop to do the filling in my iron HR heads.   

The intake might be more the issue than the heads if it's the one i'm thinking of with a gigantic plenum volume and huge runners.