in my opinion the best set up for performance and mileage and reliability would be a single 4 bbl set up. They usually use a holly 390 cfm carb. I lost about a mpg when I put one of these on my 270. If it is set up properly you could get better mileage, but don't plan on it. You will have to find some source of heat for the manifold as it will no longer be attached to the exhaust. It may be eazier to hook the accelerater up with cable. I bent some rod and used a scavenged bell crank from the junkyard. It worked ok after I got it adjusted.