My BBB 455 with a 750 Holley when cold starts to sputter or miss a little when accelerating. What would be the cause of this? Also I have a front main seal cover oil leak. I purchased the new seal. Anything I should know before tackling this project? Mike
Are the exhaust crossovers blocked in your heads. This would cause cold stumbles. Mine are blocked and no choke on the carb. I just let it warm up a little by holding the RPM's up for a minute and then drive it easy till it warms up. My stock GS has no problem, but the need for more power on my 455 car, I blocked the heat risers, plus it saves the intake paint.
I am unsure. I do have recipts of the engine builder and have failed to contact him. The car was not done by me. I would have had TSP build the engine. Someday I will get one of there's. Mike
Its easy. Take off the 4 bolts holding the bowls on and the jets are right there. It can take more time if the gaskets have been on long since you have to scrap them off.
I've actually been dealing with this myself lately. Your main jets or accelerator pump discharge nozel will most likely be the cause. The discharge nozel is a really easy swap. Right in the middle/ top of your primaries. No disassembly required. Atleast not with my street avenger. Main jets are another easy one but take slightly longer than the discharge nozel. First empty out the bowls by removing the lower left or right bolt from the bowl. Be ready with something to catch all of the fuel as soon as you remove the bolt. Next remove the remaining three bolts and bowl. The jets will be right in front of you. Be certain to have new gaskets available. Keep in mind that depending on wether or not you have a 30cc accelerator pump or 50cc and the accelerator pump cam may also make a difference. You ought to be able to work it out with your main jets and accelerator discharge nozel though. My advice; Call Holley! They're pretty good at this sort of thing.
Oh ya, and Buicks4speed is correct. The carb is most likely jetted lean for your engine or needs a larger discharge nozel. I originally thought mine was going to be too rich as I was under the impression that universal carbs were jetted rich for safety reasons. I was also at 2700 feet which supported this. As it turned out the carb was way too lean. The Holley guy (I called) said their carbs are intended for lower compression engines at sea level out of the box. He told me a stutter/hesitation was an indication of a lean condition.
Ok Wow! Thanks for the advice. I will have to get the gaskets and get busy. I really have enjoyed learning how to fix my Buick. Thanks to those that provide the advice. Looking forward to the carb. work. Mike P.S. I got her (the car) up on blocks right now as I'm switching out the front coils again. Then replacing the front cover seal.
