Originally Posted by polyspheric
The big advantage to boost... since power can be produced at far lower RPM* than NA, you don't need $4,000 rocker arms, fabricated intake manifolds, stepped-tuned headers,1,000 lb. use-it-50-times-and-throw-it-away valve springs, $$$ connecting rods, and billet cranks.
How to tell which common engines work well with boost (produce X power from Y inches @ Z boost)? Everything produces more power with boost, but is there a reliable predictor for "if it does this at ATM it will do that @ 40 psi"? No. Port flow CFM and valve area per cubic inch, rod ratio are all factors but none are linear.
What to do? Use what everyone else uses (LS, BBC, Gen-2 hemi), or you're stepping way out on thin ice. Some untested engines may surprise you (how about the 289 Studebaker?), but others will produce hundreds of HP less than those mentioned at the same boost level.



* 8,000 RPM is not 33% more inertial load than 6,000 (8K ÷ 6K = 1.333), but 78% (8K^2 ÷ 6K^2 = 1.778).


Yep! It's nice to be able to drive something now and then that idles smoothly with normal street manners. Turbo motors are like Jekel and Hyde, once the turbo spools up it goes from Harvey Milk toast to hang on for dear life!