It really depends on what your looking for. I purchased a 71 Z It was all original but indy cylinders heads built the engine, stroked it to 383 and used a Hydraulic
XE 268H 224-230 110 cam. it had super strong low and midrange with 373 gears and the Four speed. but at 10.5 to 1 and California fuel. Boy did she rattle. So to bleed off cylinder pressure and get back to solid lifters. I installed the Nostalgia Pluss 12-673-4 247-254 112 .012Lash.. Best Sounding cam Ever.. Lost all its torque and dead on the top. And this was a 383.. I figured it would hate the stock exhaust.. But no more knocking.. I installed shorty headers and a low restriction transverse system. Now she had Killer mid and top end power.
When I was building my 69 Z engine I was planning on Dropping the compression to 10to1 and using this Comp XS 274S-10 236 242 110 .500 This would of made that little engine run much better than its high compression big cam factory setup. And been pump gas friendly, still sound great. But after tearing down the engine and seeing every factory part still there, I didn't have the heart to change it. and rebuilt it all original.