The truck weighs 3400lbs, so you are to high on the hp. I use Dads Pro version Performance Trends engine analyzer and drag strip analyzer programs. It all ways comes out to 145 flywheel. My header was 1 3/4" tubes, short primary length into a 3" collector. Our program wants 1.5 about 30" long with a 10" long 2.5 collector, using the actual air flow numbers. Dad also has a Superflow air bench for checking heads. The intake is all home made using the stock intakes measurements. Each carburetor flows 70 cfm, so all three work as one. Together they are not as big as a single Monojet. Joe
