i have stock heads,cam with edelbrock performer 289(lil small), edelbrock 600cfm carb an the car runs good. 13.6@101 2.13 60ft an street tires

 

Good luck with that, hahaha!!!

 

LOL

 

You can also calibrate a Holley 850 DP, no spacer, and set it it to work right...... Overcarbing a SBF is BS, provided you know what you're doing and really understand carburetors.... BTSTDT...... 20 years ago.

 

While it is possible to jet and adjust a very large carb to run fairly acceptable on a sbf the one thing you can't overcome is the air speed coming past the boosters. If the engine wont pull enough air through the big venturis the signal will be poor regardless how it's jeted or adjusted and it will suffer on the low end. You really don't want a carb that only starts working at 3000 rpm. The best thing to do is match you carb and intake to what you have. Unless you have extensive experiance with carbs and have a few boxes of pump cams, jets, air bleeds, pump nozzles and gaskets the best thing to do is stay away from a carb is much to big for your application. You will end up with more money tuning the wrong carb to work acceptable than to buy the carb for your car that is optimal.

 

Oversized carbs only work if they have a sensitive metering circuit, which would require a well developed emulsion circuit, good boosters(down legs at least, but preferably annular) and excellent venturi design. You can get it to work, but it will never be optimal. Any wrong sized carb, too big or too small, no matter how you set it up will never work as well as the properly selected carb will. Most street 302's don't need anything bigger than a 650, and that's on a well built 302. The reality is the peak power may lose out, but only by like 5-10hp at MOST, but low rpm throttle response and mileage(where a street engine spends 95% of it's time doing work) will be better.

In order to lose over 5hp from too small of a carb you need to have an excessively small carburetor, like a 500 on a built 347 for instance. A bigger carburetor though, while it might make a couple more peak hp, will cost power everywhere else.