ok so I have 2 crabs a holly 750 dp and a edelbrok 600 cfm
and what kinda power should I expect?
have everything in the car done and installed but headers and carb, spark wires
please let me know what you think?

the engine is a sbc 350 .030,
vortec heads mild port and polish
high rise intake,
comp cam xe275,
flat top piston 2 valve relief 10:4:1 compression,
700r4, built stage 3 shift kit,
2700 stall,
posi rear from 1995 lt1 camaro(not sure the gearing),

 

i think you'll like a 600 vac secondary.

 

the eddy will work good for the street, for the best performance i'd go with a holley 650 double pumper. 750 is too much. I don't like vacuum secondaries.

 

cool so with the holley ( i prefer holley aswell) 650 what kind power should AI expect?

 

maybe 375 to the flywheel

 

I wouldn't pull an Edelbrock off an engine if someone was going to give it to me. There are only two carbs made, Q-Jets and Holleys. A vacuum secondary carb will give you better, more consistent acceleration. It provides high velocity air though the primaries at slower engine speeds increasing cylinder fill and as the engine needs more air, opens up the secondaries. I've heard the vacuum vs mechanical arguments for years. I live a 1/2 mile from a drag strip and have stood down there and watched the mechanical secondary guys bog on the starting line because of the immediate and massive loss of manifold vacuum when the carb opens on take off. My carb is a little oversized for the engine. It kills enough bottom end torque to keep my tires hooked to the ground so I'm moving forward instead of spinning. Then it opens up and really turns hard from 3500-6800.

I have a similar engine and run a 3310 Holley. That would be a 750cfm vacuum secondary with manual choke. I've removed the choke, not for any real performance gain, but just because I didn't want to run a choke cable in my car and the factory electric choke system wouldn't operate the Holley electric choke I have. A 1850 Holley (600cfm vacuum secondary) would give you a little quicker bottom end, and depending on how many RPM you are turning, wouldn't affect the max RPM noticeably.

 

I've got a similar setup as yours:

355 flat tops, vortec heads, edelbrock rpm intake, lt4 hotcam, 3.27 w/ 3000 stall.

I had the holley 3310 780cfm vacuum secondary carb and the 650 double pumper street hp carb. I've gone as fast as 8.10 in the 1/8 on both carbs. For driveability the smaller 650 wins hands down, for gas mileage the 650 wins hands down, for performance well 1/8 mile times were the same, but with the 650 when I stomp on it, I get all the power immediately and I can go sideways from a 30 roll. A vacuum secondary will never have instant response like that, you can play with the springs all day, I ended up using a purple, the yellow would bog, it still wont be instant horsepower like a double pumper. I haven't run the edelbrock on this car yet to see what times it would run because I need to get the adapter for the 700r4 tv cable.

If your double pumper is bogging you don't have the right pump shot.

Personally i'd use a edelbrock or a quadrajet over a vacuum secondary any day. I've got a 600 double pumper on another 355 and it is too small im running the edelbrock on it until I can get a 650. The edelbrock runs great on the street, but for best performance you gotta go with holley.

 

What size edelbrock? Im debating on a 750cfm(reg. edelbrock carb.) or a 650cfm(AVS series)

 

either one would work, the avs is better because you can adjust when the secondaries open.

 

I was just trying to decide which one would work best with my motor. Im running all msd & was thinking that a 750 would b fine, but now im 2nd guessing myself bc i don't think ill b able to burn all the fuel ill b throwin at it. Im not looking at crazy performance just reliablity. I dont' know which one would b the best overall.

 

go with the 650