Well I don't want to lose compression at this point. If a turbo comes along eventually I'm ok with 5.6 heads for better flow. Really just want to know about cam specs. I have '73 DJet US motors,117.982/984 I believe, one sel one slc plus another torn down sl. 78/79 kjet 117.985 and an alum 116.9xx 3.8 US TURD. Plus two 5.6 U.S. Motors available for parts. My 4.5 117.985 kjet in the car will be aimed at high revving. Manual trans makes it much more livable and it's not a street cruiser at all. I just want the best cam and head combo I can put together. Highest compression and bigest lift/ duration. I'm thinking of retarding the cams for top end power. I will prob do a little port work if I end up changing heads.