what size pushrods to buy for Coast 306/Thumper?

Hey folks,

I was going to put my new Thumper heads on my existing shortblock but I have a Coast 306 coming! What type and size of pushrods should I acquire? I saw an earlier thread about NOT buying compcams. How do I know what size I need? Does head gasket thickness matter? (I will be ordering Cometic gaskets soon, and they have a choice of thicknesses if that matters)

I have a coast 306 on order and Thumper E7s ready to bolt on, with a Jay Allen Cam ready and TMoss upper/lowers (can you say sleeeper ) .

Thanks in advance!

Sorry if this is a rookie type question.