Originally Posted by Johnboy429bbf
Just beef up the 351. Flat top pistons rv cam and a intake and r bbl carb. With mechanical secondary. And headers I built one like that and it ran well in a f150 with a c6 with a manual shift body kit. I even placed a few times in half to. Truck phlls.
I'd prefer a vacuum secondary over a mechanical secondary on anything that is very heavy or doesn't have very deep gears in the rear. A mechanical secondary needs a vehicle where the engine can rev up very quickly after that throttle is pressed and the shots of fuel are dumped in, else it will bog. A dentside F-150 with 4.11s and a nonlockup transmission like the C6 might be able to get away with it, but only when it's empty. I've seen a few guys try to pull a trailer with mechanical secondary carbs and it is not pretty.