I am running 243 heads which have the longer ls6 valves. I am putting in the gm asa cam. Would I run the 7.35 pushrod? Can I run a 7.4 rod to give me
.575 lift? Would the stock 04 ls6 springs be ok at that lift?

ANY HELP WOULD BE GREAT, THANKS

 

The valve stems on the LS6 heads from memory are 0.025" taller. The pushrods will not determine the lift, the cam will. The pushrods will determine how much preload you have on the lifter, of course unless they are way too long and bottomed such that the valves don't close. Stock pushrods are 7.385" by my measurement. 7.400" should work but it is always best to measure to ensure you have the correct geometry and lifter preloads.

 

ok, thanks. On the preload, iIjust know to check it by turning it by finger tip. Any other ways or tips?

 

You can either use an adjustable pushrod to get a zero lash measurement and then subtract that from your 7.400" pushrods or use a dial indicator over the top of the pushrod cup and tighten the rocker to just take out the clearances, zero the dial indicator and then tighten. The dial indicator will provide the preload.