While rebuilding my 350 TPI motor, i plan to replace the pushrods, what kind are good for my new motor with a little more compression? I have the Keith black pistons plus the LT4 hot cam. You need to replace the pushrods when rebuilding a motor, correct?

 

Generally yes, but they have nothing to do with pistons or compression.

With the bigger cam, you'll probably need slightly longer than stock ones. The only way to know for sure, and get it right, is to use an adjustable push rod, after the motor is together.

http://www.competitioncams.com/catalog/278.html