I've got a question, im in the middle of building a 377 and was woundering witch carb to use (750cfm dp or a 850cfm dp) my cam is
.600/.610 lift with 260/260 dur. and my cr is 10.4:1.....
Thanks

750cfm will be plenty. On my 383, I just put on a new Holley 4779 750cfm mechanical secondaries.....man, that carb is awesome! I like it better than the Demon.

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383 Speed-O-Motive stroker kit with Speed Demon 750, RPM intake,Proform HEI dist.MSD6a box,World Products Sportsman II heads, ported and polished with 2.02/1.60 valves,64cc,TRW forged pistons with 10.7:1 compression, Comp Xtreme 284 cam,Crane pushrods, Comp Cam 1.6 full roller rockers,ATI damper, 40 series Flowmasters, 4.11 gears with TH350 and Hughes 3000 stall.Powertrax NoSlip Locker

Do not use an 850DP on any street car even a big block they have terrible part throttle metering. The design is real bad the venturis are too big for the throttle bores.

680-780 thats what i like to stick with even on a BB i go with a 780 if it is no to far out there

All of the above advice is right on the money. I will just say that I have a Holley HP series 750 double pumper on my 383 and this is an awesome carb. Once I tuned it to my application I was very impressed. Very crisp, I have nothing bad to say about it. The air horn is already removed (actually designed without an air horn) and all the performance updates are all installed when you get it.

Royce

Know a guy that runs a 377 at 11.06 ET( 150 shot of N2O in a 3100 lb car) He went from a out of the box 750 to a race preped 850. Didnt gain a thing. Guess 750 was all it needed.

Based on some of the basic engine formulas on www.mortec.com (http://www.mortec.com) you could run a 377ci. engine up to about 7000RPM before you would exceed 750CFM.