I own a '71 C20, 350 eng, TH350, long bed, coil rear springs, 4:10 posi rear. I would like to install a 454 BB, and I'm concerned with clearance for headers. This engine is currently installed in my '86 K1500. *Also, I know I've got size issues with an aftermarket "Be Cool" aluminum radiator. Do you'all know of anyone installing a 454 in a stock C20? I believe it should bolt right up to the TH350. Thanks in-advance for your comments & info.