Holley carburetor question

eddie c · 08-03-2012, 02:15 PM

I recently did some work on a guys car,its a 68 Camaro with a 350ci
engine,700r4 trans,and a 4.10:1 rear gear. The engine has a mild cam,
not exactly sure of lift and duration. Anyway when the guy had the engine built a few years ago it had a 780 cfm Holley. At that time the guy was very happy with the performance of the car,now the car saw about three different people work on it over the first few years. Each time ,things were modified or changed,I dont really know what was done,however one of the guys that previously worked on the car changed out the carburetor, he put a Quadra Jet with an adapter plate on it and after that the car really performed poorly. Now I come into the picture,and suggest that we go back to a Holley because the intake,Elderbrock Scorpion, is designed for that type of base.Using the carb size calculator,I take the engine size and max RPM which is 6500 and determine that a 650 cfm Holley would be the best choice. After changing jets acc.pump nozzles and spark plugs
the car starts running really good,unfortunately no et slips,just seat of
the pants. Well long story short the guy says he wants to go back to a
780 cfm carb. I have explained to him that the carb size recomendation
was within the correct limits. What do you guys think? Will this car
run better if we go to a 780 cfm carb? Thanks for reading such a long post. ed

08-03-2012, 02:15 PM	#1
eddie c Junior Member Join Date: Jul 2011 Location: Southeastern Pa. Posts: 53 Likes: 0 Liked 0 Times in 0 Posts	Holley carburetor question I recently did some work on a guys car,its a 68 Camaro with a 350ci engine,700r4 trans,and a 4.10:1 rear gear. The engine has a mild cam, not exactly sure of lift and duration. Anyway when the guy had the engine built a few years ago it had a 780 cfm Holley. At that time the guy was very happy with the performance of the car,now the car saw about three different people work on it over the first few years. Each time ,things were modified or changed,I dont really know what was done,however one of the guys that previously worked on the car changed out the carburetor, he put a Quadra Jet with an adapter plate on it and after that the car really performed poorly. Now I come into the picture,and suggest that we go back to a Holley because the intake,Elderbrock Scorpion, is designed for that type of base.Using the carb size calculator,I take the engine size and max RPM which is 6500 and determine that a 650 cfm Holley would be the best choice. After changing jets acc.pump nozzles and spark plugs the car starts running really good,unfortunately no et slips,just seat of the pants. Well long story short the guy says he wants to go back to a 780 cfm carb. I have explained to him that the carb size recomendation was within the correct limits. What do you guys think? Will this car run better if we go to a 780 cfm carb? Thanks for reading such a long post. ed