I have a quick Question, I have a 350 H.O. engine in my 85 z28
it had a 650cfm Holley Carb on it but was old and had to be replaced.
I went to a Holley 750cfm Double pump Carb. Was that to big of a jump?
Nothing really done to the engine that i know, Vortec heads is about it.
Winter time (which is now) it seems to run a bit rougher and start up is a little longer to do. Is that normal? During the summer i take it to the track sometimes, Just wondering if id make more power with going smaller or the 750 i have now.
Im running about 13.9s. If you could get back to me when you have the chance that would be awesome. Thanks everyone! =D

 

Do you have a choke on the carb? If not, they can be a bear in cold weather until the engine warms up. If you do, then you may have to make some choke adjustments.

750 is bigger than necessary, but not necessarily too big. On a 350, a 750 double pumper should be fine going WOT from anything above 1500 RPMs according to http://www.holley.com/data/TechServi...Carburetor.pdf

But, if you use their "interactive" carb selection feature, they'll tell you to use 570-650 CFM carb, and no mechanical secondaries on a car heavier than 3100 lbs. Can't agree with them there, as they're being overly cautious with customer satisfaction.

I would agree that a smaller carb would probably run better overall. A 600-650 double pumper would improve throttle response without sacrificing high-RPM power.

Of course, all of this assumes something more than a stock cam, stock exhaust, stock gears, and stock stall. Since you didn't really address any of those items, I may be assuming too much.

 

Its an electrical choke.
My engine http://www.jegs.com/p/Chevrolet-Perf...19588/10002/-1 With Vortec Heads.
Flowmaster Exhaust( but i dont know for certain what kind of flowmasters). Ummm stock gears 3.23. Thinking about changing my torque converter. stock stall atm i assume.
its Auto 4speed 700r4 tranny with a shift kit in it, i dont know what kind though.
Does any of that help?
I appreciate your quick response =)

 

i got a eddy 750 that was just rebuilt has not had gas in it yet i will sell it cheap i got a 750dp now.