The 353 govt surplus engines that I have seen have aluminum blocks, Much lighter than cast iron. I have seen several installed in 3/4 ton trucks. There was a 74 chevy 3/4 ton 4wd with a cast iron 353 around here in the 80's . As I recall the owner told me all he did was add an extra leaf to the front springs, he also said it had about the same power as the old 6,but got 20mpg loaded. This conversion is not for a novice,you have to be able to weld and fabricate,but one good thing is that if you use a manual shut off and don't want a jake brake the only things you have to wire are the starter and alt. no computers or complicated wiring. One other thing is parts,Detroit parts while not cheap are considerably less than cat, cummins,isuzu and most other makes....Mike
