demon 500cfm 2bb carbAFR 165 heads 58cc chambersstock 77 302 2bbl manifold ported to match heads (egr blocked off)rebuilt short block with flat top pistons about 9.1 comp.1 5/8 shorty headers stock 91 roller mustang cam (reused)I figured I could possible port the manifold myself now that I have a good compressor.Or would it be better to get a performer type 4bbl manifold and get maybe a 600cfm carb from jegs or summit that is calibrated for economy. Im thinking a edelbrock cause I see where they have them "out of box" calibrated for economy.With the gas prices going up I was thinking about a combo like this cause I want to drive the truck often when I get it built. The 2bb manifold I have is for a 302 off an older 77 truck but I have a 87 block that I could put it on. The thing is I want my build to be a performance upgrade but still be able to drive it when gas is 5 dollars a gallon. Yeah the AFR's are alot but I have not herd much bad stuff about them plus it would cost about 750 for a good port and polish & rebuild around here for the older heads and I know they still wouldn't flow like the AFR's. So I figured I could go all out and get the heads and not feel bad about it later....of course I won't be getting the heads till later....

 

Sorry guys I had the stuff spaced out where it was clearer to read but when I posted "combo idea" it bunched it together.

 

This is a mismatch of parts IMO, and it won't give you what you're looking for. If you want economy you have to build a motor that's strong at low rpms, and that means a little higher compression, a short duration cam like the the Comp 31-255-5, and a complimentary exhaust including longtubes and a smaller single exhaust. Regardless what type carb you use it's going to have to supply the air and fuel the motor requires, so jetting and bore size will have to be appropriate for the application or you'll just get pinging and general poor performance. A 500cfm 4bbl should actually provide better low rpm power and economy than a 500cfm 2bbl simply because the vacuum signal will be higher when the secondaries are closed.