[Dangerous Doug]

Checking the appropriate length is pretty easy. I just did this for a 331 stroker I'm working on. Get a pushrod checker from summit racing, and you can find good instructions on the web for aligning the cam correctly to set the adjustment. Basically, you're centering the roller on the valve tip. (I centered mine, some will offset it based upon the direction the roller will move as the valve is pressed, but centering was fine for my lift.)

I bought two checkers (not necessary) to adjust both intake and exhaust. I also used these to check for clearance. Stock is 6.25". I ended up installing 6.50".

DD