2 650 carbs on a blown 392???

[billlsbird]

....Hello Everyone, I talked to my engine builder today about what carburation he would recommend for the blown 392 hemi that he's building for me. He said not to use any more than 2 650's. But I've always thought that this size blown motor would need 2 750's. Plus that's what the Wiend web site recommeded {2 750's}. He said that 2 650's would be more than enough carburation for my application. What does everyone think about this??? ... Thanks, Bill

oh, 392 hemi in a '32 ford. 8 to 1 compression. 6:71 supercharger, turbo 400 w/ trans brake, 3000 true stall. 4:11 true track rear end. Holley blue fuel pump w/ -8 an line.....

[kitz]

This is from BDS ..............

The size of carb(s) or CFM required for a given application can be calculated by the following formula A: {(CID x RPM) ÷ 3456} x {Boost ÷ 14.7) + 1} = CFM required. The amount of CFM required will determine carburetor size and quantity. If you try to use a carb with less CFM than required, performance and economy may be greatly reduced. Bigger is not always better when selecting carbs that are 30% over what is required, you may encounter problems in fuel distribution.

Kitz

[billlsbird]

....Thanks Kitz! so two 650's probably won't be enough carburation. It looks like somewhere between two 700's & two 750's.... Thanks again! Bill

[valvebounce]

Be sure to externally reference your powervalves if you're running holleys.

[billlsbird]

...Thank You Valvebounce, I am going to run the supercharger carbs. These would already be set up like this, wouldn't they??? Bill

[valvebounce]

I suppose? I'm not really familiar with fancy purpose built stuff. I had to modify the powervalve set up on the holley for my blown engine.