65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => The Nailhead => Topic started by: Jim on May 23, 2023, 04:13:04 PM
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Hi, according to what I have been reading lately if you do a distributor recurve intake heat block off gaskets and an 800 avs carb you can get over 50 hp making a stock 401 375 + hp can this be real???.Jim
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It will help, but not that much.
Buick offered an optional 401 for the '66 GS which has the larger Q-jet, 2x4 spec distributor, and the 2x4 cam. It was rated at 340hp, 15 hp more than the standard 401. It lost a little hp/torque at the lower rpm's but had gains over 4,000 rpm.
A faster distributor advance did help low-end power on my car. And a bigger carb will noticeably improve higher rpm power.
Only a dyno test will prove what those mods really make.
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Going to the 800 avs would sort of be like switching from a 2barrel to4 barrel I guess.Jim
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It's probably a worthwhile swap. I just don't believe the +50 hp Facebook claims.... especially without proof.
The stock air cleaner won't fit the larger opening of the AVS, but 1) a spacer can be added to allow it to fit, and 2) the stock air cleaner is restrictive and will limit power. You'll need to adapt the linkage as well.
It all depends on your goals.
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I know one car picked up a couple tenths in the quarter with the new aluminum intakes, maybe even 3 tenths. More testing ongoing!
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Jim, is that Stark's car? What carb is he using?
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Yes, he?s trying different carbs, Qjets.
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Used to be Rule of thumb ,.10 sec=10hp if old age isn't getting me.jim
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Has anyone experimented with a roller cam in a nailhead?