I have a kickin' 4.9L in my old truck. Rebuilt the engine with stock cast pistons, added a Comp cams 260H cam, and headers, w/4bbl intake. Ran like a raped ape. The 4bbl intake REALLY needs a heat source for winter use though. Ended up swapping over to factory EFI manifold w/custom controller to fix the poor winter operation. It still runs good, but the truck is too rusty to drive anymore, so It's parked permanently.