If you don't like the turbo plumbing, how about a M-90 Eaton off a Supercoupe or one of the Blower Pontiacs? (speaking for the 235 / 261, a 270 / 302 would likely want a M-112)
Might not make 300 Hp, but the torque would be there (you would have to wind the engine some more for the Hp, requiring cam & head work to optimise).
As far as $ per Hp, none of the stuff we discuss on this forum makes any economical sense.
IIRC Fontanna has a parts assembly (dare I say "kit") that's supposed to make 300+ (320~340 I think) out of an otherwise "stock" Jimmy 302 (12 port head assembly, intake, exhaust, rockers, pushrods, tappets and cam) for $7000 ish (maybe $9000 now that the dollar is further down
).
I was told that was the "street" tune (single 4V, & Iron Manifolds) but that was from a 3rd party, not from the orriginal source so the numbers may be out of date (I hate it when my numbers get old
).
