johnny, I have a 427 tall deck block, bought it on ebay, if figured i could use an Hei distributor from a 366 tall deck (i know where a few donors are)the 366 had a highrise 4 barrel intake manifold (not spreadbore) kinda like the ones that came on the big block camaro /chevells (someone correct me if i'm wrong) if i don't use that, there are aftermarket performance tall deck intakes, other wise yes i'll have to use spacers, i don't think i'll have a problem with headers in an 85 chevy truck, oil filter will be no problem the one ton trucks came stock with a 454. i thought some where around .500(at valve)or higher for lift in the cam, 9:1 to 10:1 comp, some time down the road i want to get late sixties early seventies camaro i figured i could build the motor mild for the truck then go wild and dump it in the camaro