[Huck]

I was the guy Andy referred to with trial and error testing intakes--and headers. Started with crate--and stock with just HEI and Edel 1406. Was getting like 16mpg--went to OD 5spd and that kicked up mpg like 3--to 18-19mpg hwy. Then did headers and 2101 edel intake and lost 3mpg. If you look, the stock intake has small primaries (front) which work like a restrictor plate. I tried headman then hooker headers--totaly waste--was running straight duals which I should have had spliced together down stream for maximum perf butttt- I backed off to stock ram horns and regained 2mpg then back to stock intake and got another 2mpg and could get 20 mpg hwy crusing at 70. My low end torque was back and I didn't really care about high end power as the truck didin't like running over 90 anyway---way too much wind resistance. That's my story and I'm sticking to it. Best investment was the 5speed OD by far!!
I kind of think that headers and custom intakes need matching heads and cam shafts to give you any significant positive results. Huck