wouldn't a smaller base circle cam would require longer pushrods?

 

yes and larger base circle a shorter PR. other variables also contribute to PR length. Block & head milling and head gasket thickness

 

You generally use taller lifters. If you don't you run the risk of the lifters turning inside the bores and eating the cam up.

 

Having the narrowest sweep is more important than being perfectly centered over the valve tip.

I think you need to read over a few online tutorials on finding pushrod length and start over fresh because it doesn't make any sense that you should be using a 7" rod with that setup unless the lifter PR seat is higher than your old lifters...which with a GM LS7, it shouldn't be as that's the superceded part for all factory HR applications now.

 

these are Delphi SBC lifters, many prefer over the LS7 ones

White Performance Detail Description

 

OK guys been chatting with Rob I believe from shbox website and finally found the problem I was doing it wrong I was not at the base of the cam so I now know I will need longer pushrods thanks guys for all your help and thanks to shbox now just have check what length push rods the ones I have going to be to short

 

yep, confirming you are on the base circle of cam is important