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Discussion Starter · #1 · (Edited)
getting ready to build a stroker motor from a block I scored . Bought the lower assembly from butler . I plan on buying their 87cc aluminum heads but can I port , gasket match a factory intake to install on this motor ? I plan on debadge the heads and make it look as stock as possible. The carb I have now has been rebuilt for a stock 400. I assume I have to send it back out to get bigger rods and jets installed.. 7040263 750 qjet
 

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You might be surprised at how well your carb works on the new engine. One of the great things about the Qjet design is its ability be diversified.
 

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Discussion Starter · #3 ·
Well butler p is telling me the stock intake can’t be ported enough to match the heads and I figure that carburetor might run a little lean
 

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I did a stroker build on my 69 GTO 400 last year, and in the Dyno she would run lean with the Q-jet I had modified. It has Edelbrock aluminum heads modified by SD Performance, a stock intake manifold CNC’d by SD performance, a custom ground cam, etc. She made 512 hp at 5,400 rpm and 556 lb-ft of torque at 3,900 rpm. Here’s an article about the build and Dyno day: 462-Inch Stroker Pontiac 400 Makes Over 500 HP, Looks Stock.

Still got impressive numbers from it, but after the Dyno run, I purchased a modified Q-jet from Sean Murphy. Here’s their website: SMI Carburetor SMI- Sean Murphy Induction. They are in Huntington Beach, CA. If you call Sean, he can tell you what you need and what it will cost. He’s a great guy. Good luck with your build!

Wick


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Discussion Starter · #5 ·
What did SD end up doing with the intake manifold .. I’m all about the power but does your car idle smooth? Enough vacuum for power brakes? I have 14” tires on this car and would like a nice tame stroker , not a teeth chattering burn out machine ..
my car is numbers matching too and I figure I build a stroker and run it for a couple years while I’m building the original engine . Sure I can sell the stroker later to recoup costs .. I scored a 69 block , intake and carb for a good price .
 

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What did SD end up doing with the intake manifold .. I’m all about the power but does your car idle smooth? Enough vacuum for power brakes? I have 14” tires on this car and would like a nice tame stroker , not a teeth chattering burn out machine ..
my car is numbers matching too and I figure I build a stroker and run it for a couple years while I’m building the original engine . Sure I can sell the stroker later to recoup costs .. I scored a 69 block , intake and carb for a good price .
SD uses a CNC set-up and then I believe hand ports to finish. No need to really port match the intake as the ports will be smaller than the heads and no real advantage because the overall ports themselves will be the restriction.

However, you can certainly do this using the intake gaskets for the heads which will be RA IV. Port to match the gaskets and then blend back into the intake 1-2". Then clean up the runners with sanding rolls. This full process will help, but just port matching may not do a lot for the given time involved.

The other trick will be to open up the intake under the carb and use a 1" spacer. This will help flow more air as well. Read more here:



The RPM Performer is a better choice if going aftermarket, but will raise the carb up higher.

The 750CFM Q-jet can work, but you may be giving up some HP/TQ. The 800 CFM may be a little better. If using the stock intake, I would go with it. The noted Q-jets above seem to be a good choice and can be tailored to your engine build if you don't want to rebuild and go through yours.

The cam outlined in the above article is also a good cam pick, not too aggressive in a stroker. Should have plenty of pull.

You will also want good flowing exhausts, either matching RA cast iron or headers and 2.5" mandrel bent pipes.
 
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