I’m trying to figurate what size I have on my Holley. Easy located numbers I have found: 80770-1, 2075, 10569, 8051b Would anyone of these say anything about the size? I never felt any real engine strength last summer so I wondered if the carb might be too small. If I slowly cruised for a while and suddenly accelerated fully, then it would backfire and die. (Might be bad ignition parts also, replacing all of it now. Or just not adjusted rightly.) Thanks
That is a 770 cfm carb. http://www.holley.com/products.asp?product=0-80770 Probably is a little small. You need to tell us more about your 455 so we can help.
Thanks. It’s a rebuilt 430 with new stock parts (I think, I bought the car with the note that someone locally known Chevy engine rebuilder handled it and it was done with original setup – no racing parts or such things.). Except the carb… Should it be 850cfm?
The size is close to the stock qjet.... three things, first do a compression test, then, make sure the engine electrical is good ,,,, then , and only then start working with the carb.... if it back fires back thru the intake then look at ign timing being too early or the carb jetting being to lean, or the accellerator pump not putting out enough fuel,,,,, If it back fires thru the exhaust pipes, it indicates late ign timing,,, or cross fire,,,,, but ,,,, what you are describing is classic for a ''lean out'' backfire.... With my holleys , if they were doing that , I would stretch the secondary diaphragm spring a little to make them open later, and/or make sure the accellerator pump is putting out a long lasting, stream of fuel at the nozzles.... A 430 will take a big carb with no trouble, I ran a 950 holley 3 barrell on mine and it ran super strong.....could have handled a 1050.....