[BlackBird68]

I am starting to plan ahead for my engine build just to make sure all calculations and part selections are correct. I am not in a buying mode yet but just starting to throw some ideas around and any info or advice would be great.

First I should say this will be a street car running on high oct gas and I want to put down around 500 ponies and 550+ lbs of torque. That is the benchmark so...

What combination would I need if I went with a 400 motor as opposed to a 455?? I am planning on going with aluminum heads either KR or Edel for performance and also forged internals except the crank.

Any thoughts? As always thanks guys

[steve25]

If you are saying you are leaning more towards a 400 motor then your set goal HP numbers can be had in street trim with heads flowing in the 270 Intake cfm@28", but the torque numbers will not be reached with a 400 in NA breathing form!
550 plus Torque is a lot to ask from a 400 in livable street trim with out 11 to 1 or greater compression.
You will need to pump it up with boost, or spray it.

[Cliff R]

+1

No problem at all getting plenty of power from a 400 engine, but it's going to need compression and rpm's to run with a milder 455 build.

The last time we had a 400 on the dyno with KRE heads (65cc), it easily made 440hp with a relatively small cam in it (Crower 60916). The larger 60243 cam made 450hp, and the 60919 cam made 460hp. The 60919 was WAY too much cam in that build for a street engine, IMHO. Idle quality was horrible, low vacuum, sluggish off idle, and it made about the same power thru 5000rpm's as the smaller cam.

None of those engines made over 470ft lbs torque from what I can remember?.....Cliff

[72LuxuryLeMansLa.]

Originally Posted by BlackBird68

I am starting to plan ahead for my engine build just to make sure all calculations and part selections are correct. I am not in a buying mode yet but just starting to throw some ideas around and any info or advice would be great.

First I should say this will be a street car running on high oct gas and I want to put down around 500 ponies and 550+ lbs of torque. That is the benchmark so...

What combination would I need if I went with a 400 motor as opposed to a 455?? I am planning on going with aluminum heads either KR or Edel for performance and also forged internals except the crank.

Any thoughts? As always thanks guys

Stroke that 400 to 455 and add SD performance's HR Old faithful and 290cfm kre heads and they say you will be in the 550hp and 600ft. lbs. of torque neighborhood. I'm sure that there must be 50 guys on here running that combo and can testify to it's validity.
I'm personally going the 428-stump puller route to make driving on wet streets a little easier.

http://www.sdperformance.com/listPro...p?categoryID=2

Karl

[i82much]

Not sure how much you've looked into this but there are reasonably-priced stroker kits out there to get you a 4.25 stroke in a 400 block, for not too much more you can get a forged crank to go with it.

[HaloMedic]

Stroke it, thats my goal , ive got a great running 455 now 430 to 450 HP, Ive got a 70 WT block going to stroke.
To build up a 400 is gonna cost stroking a 400 is just a bit more,
And the feel factor your gonna love with a stroker thats priceless

[ta man]

Originally Posted by 72LuxuryLeMansLa.

Stroke that 400 to 455 and add SD performance's HR Old faithful and 290cfm kre heads and they say you will be in the 550hp and 600ft. lbs. of torque neighborhood. I'm sure that there must be 50 guys on here running that combo and can testify to it's validity.
I'm personally going the 428-stump puller route to make driving on wet streets a little easier.

http://www.sdperformance.com/listPro...p?categoryID=2

Karl

Plus the SD combo is a smooth low idling street combo that runs on regular fuel.

[BlackBird68]

Originally Posted by ta man

Plus the SD combo is a smooth low idling street combo that runs on regular fuel.

that is actually what I forgot to specifically mention but intended to. I do want to steer towards a smoother low idling street combo.

Thanks for all the advice guys, time to crunch some numbers and stats and see what I come up with.

I have a 400 block from a '68 gto but it needs to be bored .040, I am not sure if it is a good candidate for a build like this though because of the bore and my plan to throw on aluminum heads...etc, I think the CR might be too high.

Should I find a standard bore block?

[72LuxuryLeMansLa.]

Originally Posted by BlackBird68

that is actually what I forgot to specifically mention but intended to. I do want to steer towards a smoother low idling street combo.

Thanks for all the advice guys, time to crunch some numbers and stats and see what I come up with.

I have a 400 block from a '68 gto but it needs to be bored .040, I am not sure if it is a good candidate for a build like this though because of the bore and my plan to throw on aluminum heads...etc, I think the CR might be too high.

Should I find a standard bore block?

These three books should be enough to get you where you would like to go:

How to Build Max-Performance Pontiac V-8s, by Jim Hand

Build and Modify Rochester Quadrajet Carburetors, by Cliff Ruggles

HOW TO Rebuild PONTIAC V-8s, by Rocky Rotella

Karl

[ta man]

What kind of budget do you have?

[GR8ONE68]

If you go with a 3.00" main 4.21" crank, .010" over 455 pistons (same bore as a 400 with .040" over bore), SD ported KRE 290 cfm heads, the CR will not be too high. You could even take that 400 .060" over and get more cubes. If you go this route with standard '68 iron heads, then yes the CR would be too high. You can do it with 6X heads but you won't get the peformance of the KRE heads.