Hot Rod Forum banner

Holley 600 vs. 750

8K views 6 replies 7 participants last post by  engines 
#1 ·
I have a 78 chevy 350 bored 60 over. 9.8 to 1 compression .502- .510 lift cam. Is my 600 cfm holley too small will i see a benefit with a 750.
How much benefit? is it worth it?
please help
 
#3 ·
There's an old rule in selecting the right CFM for your engine, and it still holds true today. You have a 350ci, 350ci X 2= 700, so you want to select a carb around 700 CFM (650-750).

Comes from how to build HP volume 1.

[ January 19, 2003: Message edited by: 87442lover ]

[ January 19, 2003: Message edited by: 87442lover ]</p>
 
#4 ·
It would be hard to give you an accurate answer without more information about your vehicle and engine. Is this a pickup, car, lightweight ,heavy? Are you running an auto, manual, stall converter? You have a cam that would be considered large for street use if I am correct in assuming it is a hydraulic? Have you also upgraded heads, intake, exhaust? Some might disagree, but a HEALTHY engine can use nearly 2cfm per h.p.! So, if your engine is at or above 350h.p. then a carb up to 700cfm is in the ballpark! I would suggest that you look at the holley 670 avenger if you are running an auto, or a 650 to 700 d.p. if you have a manual!How much benefit? That is all according to how well you have matched parts that work together! And if the carb is the engines limiting factor (or weak link) at this point! Good Luck!
 
#7 ·
I have the same set up and tack 8,000 rpm and use a 650 spread bore and kick *** . Use the holley book to find the right size carb for the size and rpm you will be actually be useing. It works, I race others with 850 holley on sprit car engines, tunnel rams ect..and they are loosing.I even use a stock spread bore manifold but have 11 to 1's and a circle track cam in a 57 chevy pick up-sleeper.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top