well the 240H is as close to direct bolt on as you can get, designed to run well with EVERYTHING else being factory stock, even compression ratio and springs. That was my plan, a stock rebuild with an efficiency increasing cam.
I have SBC springs btw.
Anything beyond this necessitates aftermarket springs. And that in turn requires changing rocker studs from press-in type to threaded type (another $120 trip to the machine shop). The hotter comp cams high/extreme energy cams are also designed to run stock compression (8.5:1) or up to 9.25:1 but you will need other mods to make them work properly. The 268H is the biggest of the series that can still use a stock torque converter, although I saw some people disagreeing. That's why it would be my choice for an actual performance cam without having to spend even more money on other junk just to be able to run it.
I am almost certain I will never install the 240H and just go straight to the bigger 268H. I can then fall back on the smaller cam if I don't like it, but I will need to get a new lifter set for it to break it in right and I will need to set the valve/rocker geometry again.
