JimC25
Member
So I was actually able to find some GT40 heads at a junkyard in Oklahoma to replace my stock heads. I dropped them off at the machine shop earlier today to get them checked out. I am hoping to get a little more power on the low end, but I don't want to sacrifice gas mileage. I have a 1989 XLT with the speed density 5.0 and AOD transmission. I'm definitely going to swap the heads if they check out all right, since that is supposed to give me some more horsepower, but I'm on the fence about a new cam. I'm planning to call Comp Cam on Monday to get their recommendation, but I wanted to see what others who have done this experienced. Is it pretty standard to lose gas mileage from a mild cam upgrade or does it really depend on which cam you go with? Also, I've seen alot of people say not to waste your time changing heads if you don't also do the cam swap. Has anyone done the GT40 upgrade only? If so, did it give you any noticeable gains?