I've used the carb calculators and know the 650 Edelbrock thunder AVS that I have is to LARGE for my dodge 273. This carb is left over for another build. The caluclators come up with 380-475 CFM @ 5500. I've got the smallest Summit cam, Electronic Ignition& adjustable vacuum advance. Edelbrock performer intake, dual exhaust (not headers). Can the 650 thunder AVS work well on my 273, if I rejet/and rods ? I never run hard, just cruise. I'm always looking for better MPG. Or will I be better of buying the Edelbrock 500 thunder AVS ???