stepside, is that a c10 in your sig? what year and did the bed come with wood for the floor. im askin because one of my friends has one that looks very simular and he doesnt know what year the bed is in his truck because its from another one. and he broke out all the wood because it was rotting.
The 390 CFM carb which I listed the part number for is meant for use on V-8's. While its supposedly dimunitive in size, it still flows more than do all the 2 bbl carbs out there, when all 4 bbls are open. I know Im going to get this thing about 500 cfm 2 bbl carbs etc, but 2 bbls are rated with a higher vacuum. If that 500 2 bbl was rated like a 4 bbl, it would only be flowing about 355 cfm. I am presuming you are running a stock engine, so Ill once again post the CFM formula.
CID X desired RPM divided by 3456 = CFM needed.
350 x 4000 = 1400000 divided by 3456 = 405 CFM.
A carburetor will still feed an engine way over the peak rpm point.
The NASCAR guys run a 390 cfm carb, with a restrictor plate under it with ports even smaller than the venturis in the 390 and still turn 7000 rpm, and make upwards of 600 hp. Granted you can actually have too small a carburetor but not in the application hes looking for.
The 8007 model 390 cfm is a street carb. I only mentioned it out of having used them in years past and got very good performance out of them, not to start an arguement.
The one example that I remember most was putting a 390 on a 74 Mercury I had with a 460 in it. MY gas mileage actually went up 2 1/2 miles to the gallon.
AND I didnt notice any loss of get up and go either.