396 , holley carb, runs like crap??

[Grumpy]

Hey guys. I hope I'm posting this in the right section. I've got a 69 396 big block bored to a 402 stock in a 72 Chevelle. I've got 3" headers with 3" pipes and a Edelbrock manifold. Its got a 770 Holey carb and it runs like crap. I'm looking to change the carb any suggestions would be greatly appreciated.



99.9% of the time, I've found, if the holley carbs not mechanically damaged or excessively corroded or full of trash, and your not dealing with linkage or vacuum leaks and if you have consistent fuel pressure it will simply require the skills of a knowledgeable tuner, read the links and sub-links below carefully, don,t assume anything test and isolate!
most holley carbs are both easy to diagnose and tune and parts are readily available.
obviously having a vacuum gauge, fuel pressure gauge,timing light and some experience adjusting valves and trouble shooting ignitions and fuel systems and reading spark plugs, and some experience helps
ITS NOT a huge PROBLEM,
its a fairly extensive series of little factors,
that need to be carefully checked and verified
ID suggest starting with a compression test,on all cylinders, checking the float levels and check for vacuum leaks, verify your TDC, and ignition advance curve, and that your fuel pressure is consistent, and properly adjust the valves
many guys ignore proven combos, because it may cost more than they want to spend, and either insist on using components they own currently or think they can buy far less expensively than the components, I know from experience will actually work.

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.com/index.php?threads/fuel-pressure-regulators.635/

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.com/index.php?threads/so-you-failed-emmision-testing.3522/

http://garage.grumpysperformance.com/index.php?threads/spark-plug-info.202/

http://garage.grumpysperformance.co...ouble-shooting-rebuilding-hei-ignitions.2798/

http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://garage.grumpysperformance.com/index.php?threads/holley-carb-power-valves.1639/

http://garage.grumpysperformance.co...olley-accelerator-pumps-cams.1790/#post-31534

http://garage.grumpysperformance.co...n-670-holley-street-avenger.12305/#post-60531


reading the links and sub links will help

 

[Grumpy]

I doubt you will find you can,t get the current carb correctly adjusted if you take the time and effort to disassemble and clean and adjust the current carb, but if you want to buy a good carb, to replace that one,
Demon Carburetion Street Demon Carburetors 1904
Carburetor, Street Demon, 750 cfm, 4-Barrel, Square Bore/Spread Bore, Electric Choke, Composite Bowl, Each

these work rather well.
https://www.summitracing.com/parts/dem-1904/overview/