# 400 Stroker Engine Build, Need Suggestions: Parts and Assemble



## jimmy328 (Oct 12, 2011)

Next week I’ll purchase a stroker kit, aluminum heads and other parts (possibly complete engine) from Kauffman or Butler (suggestions). I need suggestions on what to buy so I spend my $1000’s without regrets (I’m a medical guy, not mechanical by occupation). Intended use is street and interstate driving. My 67 GTO (400) currently has a 3 speed auto but will eventually have a Tremec 5 or 6 speed. The rear is from a salvage yard Chevelle with 390 gears; this too will be replaced.

"My questions":

*The Block*

My block is the original 400 CI. My local machinist has bored it to 0.060 and has magnaflux’d the block. He states the block is good but cannot be bored any more. As I understand, a “stroker kit” (for my block) requires 0.065.

Perhaps 0.005 additional boring would be okay?
Are there any genuine advantages of spending $3000 for a new MR-1 cast iron block?
(I think an aluminum block is more than I want to spend)

*The Stroker Kit*

Please advise me on this. This will be a street car and some interstate driving. I guess the question here is the types of metals to choose from; cast, forged, 4340.

*Aluminum Heads*

Jeff Kaufman suggested high ports. I read on another forum that the torque on high ports doesn’t really kick in till after 4000 RPM. I don’t know if this is true.

Will “high port heads” even fit under my stock hood?
Can I still use the Doug’s Headers I recently bought?
Would I see the true potential of “high port heads” for a street/interstate car or should I go with the basic D-ports?

*CAM and Valve Train*

I need your input here. Currently I have stock hydraulic lifters, push rods, rockers and the CAM is a Speed-Pro (basically stock but semi-rough idle). Jeff stated for a 600 HP combo, I should buy a hydraulic roller CAM and setup. I don’t know what to choose here.

*The Intake Manifold and Carb*

I have the original intake but I guess this should be upgraded also to obtain the potential of the aluminum heads.

I have a nice rebuilt Q-Jet from Cliff Ruggles; will this Carb work with Kauffman after-market intake manifolds?
Do I need a different carb to obtain the true potentially of this build?

Thank you,
Jim


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## oldskool (Apr 26, 2015)

If 400hp and 500ft lbs of torque is enuff for you, I'd go with something like this 455 pump gas 455, with 6x iron heads, Eagle rods, and forged pistons. 

455 Long Block

If you want closer to 500hp, you can go with a 400 stroker shortblock, like one of these I'll link, some out of the box KRE 85cc D-ports, and a small roller cam.

455 Short Block

pontiac crate engines

Kauffman Racing Equipment

SD Performance- Pontiac Performance Specialists

"...I have the original intake but I guess this should be upgraded also to obtain the potential of the aluminum heads.

I have a nice rebuilt Q-Jet from Cliff Ruggles; will this Carb work with Kauffman after-market intake manifolds?
Do I need a different carb to obtain the true potentially of this build?..."

The Q-jet and stock intake will be fine. If the intake is a '67 model, make sure you have the exhaust heat riser holes at the ends of the "smiley face" "hot slot" groove, plugged. These holes have caused lots of carb problems. The holes and groove was used only in '67.

Since you live in Fla, you don't need an intake with a heat crossover. And, a single plane intake will work just fine on a 455 or larger engine. So, I'd try one of the cheap Chinese single planes. They go for less than $150, on Ebay. They'll accept either a square bore or a Q-jet carb.

Pontiac 326 350 389 400 421 428 455 Shootout Intake Manifold Satin | eBay

Pontiac 326 350 389 400 421 428 455 Shootout Intake Manifold Polished | eBay

I've read that these were patterned after the Holley Street Dominator intake. So, if you want alum, but wanna keep the exhaust heat crossover, you can usually find some of the HSD intakes on Ebay.

Pontiac V8 Holley Street Dominator Intake Manifold 701R 9 | eBay

Holley Street Dominator 701R 9 for Pontiac 1966 326 350 400 421 428 Engines | eBay

Pontiac Intake Manifold Holley Street Dominator 326 350 389 400 455 GTO J7212 | eBay

Holley Street Dominator Pontiac Intake 350 389 400 455 Trans Am | eBay


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## oldskool (Apr 26, 2015)

But hey, if that ain't enuff power, the sky's the limit. Or, I should say only your budget is the limit. 

There is a 4.5" 400 block stroker, with the High Ports you mentioned.

Or a 505-535 cube aftermarket block engine, in iron or alum. And there are some exotic heads, like the RAV's and others. And you can use a Northwind or Victor intake with a street 1050cfm Dominator type carb. And you can buy any spec roller cam you want. 800-1000 streetable hp is possible today, if your budget can stand it. 

http://www.jbp-pontiac.com/products/camshafts/compcams3.html

http://www.krepower.com/Pontiac Cams and Parts.htm

http://www.spottsperformance.com/IA2 engine block2

http://www.dcimotorsports.com/products/ram-air-five-heads/

http://www.krepower.com/Pontiac Street Engines.htm

http://www.jbp-pontiac.com/products/engines_assemblies/505-541_CI.html

If you have a competent Pontiac machine shop/engine builder close by, you can buy the parts and have it built locally. Otherwise, you'll have to buy out of state and have it shipped.

http://www.spottsperformance.com/blocks.htm

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#472_523

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#541


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## PontiacJim (Dec 29, 2012)

First, your machinist should not have bored your block .060" prior to having the pistons in hand so that he can match the bore/finish to the piston. Most will bore the cylinder a bit undersize and then hone it to size, maybe this is what your machinist meant?

However, going to .065" should be negligible. You are talking .005" and a human hair is .060" thick! So you should be fine. IF you have any doubts and want to be on the safe side, you could have the bores sonic tested for wall thickness. Some machine shops offer this.

It seems you are aiming for a street car. That means different things to different people. Personal opinion here would be to keep the cam a bit on the small side. What you are going to make up in stroker cubes & torque can be enhanced with a cam spec that will compliment the combo. As you go bigger in cam, you typically raise the HP & torque band and push it up the RPM scale. So you most likely want a cam that is not about big HP, but a good overall flat torque curve from 2,500 -6,000 RPM, possible a tad bit lower if you plan on mostly street driving 2,000- 5,500 RPM's. For a roller, I like the specs on the Lunati cam 20510711LK https://www.lunatipower.com/Product.aspx?id=4785&gid=289 However, I have never used a roller so no experience talking here, I am just pointing out the cam specs and feel they would give you a good street engine with plenty of HP. Run this by whomever you decide to buy your engine parts from.

The aluminum heads are good and I think they all work with each having its own potential when modified. The thing to remember is that the larger the ports/valves, the more CFM's they flow. More flow is for more HP at higher RPM's. Too much flow and you may have a poorly performing engine at the lower RPM range, ie street driving. You want to keep port velocity up so the engine is responsive at the lower RPM's and still provide enough CFM's to carry your engine into the upper range. Again, my opinion, I feel a port that flows 240-260 CFM's would be a good street head. Read this article: Techtips - Cylinder Heads Performance Guide for Pontiac V-8 Engines

The "high port" heads refers to the shape of the port and not the physical size of the head. So same size in dimensions as your stock heads. The exhaust ports are round ports and not the D-ports. So if you got Doug's D-port headers, they will not work. You need the Ram Air IV round port style headers.

Connecting rods. The stroker kits come complete with forged H-beam rods. Any forged rod is a big improvement over the factory cast rods. The 4340 is the type of steel used. 4340 is most commonly used in connecting rods - nothing wrong with it.

Keep the Q-jet, but you will probably have to tune it to the larger cubes and bigger cam. The factory intake works well and would be very responsive on the street but you would most likely want the Ram Air IV aluminum intake which I believe is needed to match the taller ports of the aluminum heads. They make these aftermarket along with the exhaust heat crossover if you want to use it. Of course, other aftermarket intakes are available as noted by oldskool.

:thumbsup:


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## oldskool (Apr 26, 2015)

"...a human hair is .060" thick..."


I think maybe you need to move that decimal point over to the left, and add a zero. Nobody's hair is that thick. 

What is Diameter of human hair in inches


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## BearGFR (Aug 25, 2008)

Ut oh.... whoever said a stroker required +0.065 was mistaken. All it needs is +0.035 (5 thousandths over a standard 455 bore size) The reason for that size is that it makes piston choice "easy". You can still build a stroker motor with different bore sizes, but you might have to spend more coin for pistons.

The best advice I can give you is to call Jim Lehart at Central Virginia Machine. He can (and will) help you plan your build without wasting your money.

Bear


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## oldskool (Apr 26, 2015)

"...My block is the original 400 CI. My local machinist has bored it to 0.060 and has magnaflux’d the block. He states the block is good but cannot be bored any more. As I understand, a “stroker kit” (for my block) requires 0.065..."

"... whoever said a stroker required +0.065 was mistaken..."


I think he meant that because HIS BLOCK was already bored .060 over, he would need .065 over pistons. Of course, as always, I could be wrong. 

Also, Butler sells several stroker assemblies, in both 4.25 and 4.21 strokes that have 4.150 & 4.180 bore size, or any other size wanted.

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#462_468

"...You can still build a stroker motor with different bore sizes, but you might have to spend more coin for pistons..."

Most any assembly which has Ross pistons, is available with any bore size. But, as mentioned, the Ross pistons cost more. But, if a different bore size will allow you to use the block you already have, it might be worth the extra cost.

http://www.jbp-pontiac.com/products/engines_assemblies/rotating_assemblies.html#461_467


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## PontiacJim (Dec 29, 2012)

oldskool said:


> "...a human hair is .060" thick..."
> 
> 
> I think maybe you need to move that decimal point over to the left, and add a zero. Nobody's hair is that thick.
> ...



Oops, I was thinking about the diameter of my last girlfriend's pubic hairs, she was a real amazon of a woman. :lol:

Hey, I was tired dammit. :yesnod:


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