i have just put in a lpe gtv cam with stock ls-6/z06 heads. heads were decked a thou to clean em up. valves are correct z06 ltwts.

i ave it all back together and the motor turns so easily it feels like its not buildin compression....i can feel modest bits of airflow eing pshed in and out of the ports, but it doesnt seem like its enough? how much force should it take to turn this over by hand....should i have audible and subsantial air being pushed around.

lpe assured me the stock pushrod lengthe would work, but im worrying that the valves arent closing all the way with the longer stem and stock lenght pr....is this possible?

 

Are the spark plugs in the heads? If everything is installed, it should be pretty difficult to turn over w/ a regular ratchet.
I'm not sure about the difference in valve lengths, but it is possible the valves are hanging open w/ the wrong pr length.

 

pushrod length should make little difference in the effective compression you feel when manually turning the motor over. Check that the lifter stays roughly centered over the valve tip through an open/close cycle.

Also, the proper length will also depend on the base circle diameter of the cam. LS6 valves are longer to compensate for the smaller base circle of the LS6 cam. That is why the pushrods are the same length between LS1 and LS6.