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Buddy picks up 40hp on the dyno with a jet change wow


Veteran Member
Senior Member
No one friend who is a class racer said he picked up almost 40 hp just jetting the Holley on his new BBC. Last time they used it was on his old combo and seemed to run well but without a wide band you're just guessing and that's what he was going I guess. He also said that with the dual plane intake they has to crossjet the carburetor to get it right. That's a ton of power to pick up from something so simple.

Sorry I can't give you guys any numbers as these guys are pretty secretive on this kind of stuff.
Talked to a guy the runs stock & he has an O2 sensor in each tube. He's from a well known racing family.
Don't know how much gains he made but he did a lot of stagger jetting & maybe even some zip ties on boosters.
Most people could care less about gas mileage with a high perf engine, but I'd like to approach 18 mpg with my 489 BBC.
Impossible ? Maybe.
I just ordered a center body for my Holley 850 double-pumper and it has annular boosters.
Those boosters can greatly increase the lower rpm signal when the engine is loafing down the interstate in overdrive.
I now have 3 setups to try. An 850 quadrajet that's made for 525 hp and two different 850 double-pumpers,
one with down-leg and the other with annular boosters.
I will have 02 sensors installed so it should be fun tuning this.
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