i just rebuilt the topend of a 350 the bottom end is in good shape with low miles and for some reason i cant get any compression readings (0) out of it when i trurn the motor over by hand it is hard to turn so i beleive the rings arent bad and i have all new heads cam lifters any ideas of what the problem could be or things to check for? i used the gauge on my truck and it works. i had a buddy do the timing chain and i think he messed up could it have sent a valve through the piston? i never heard any bad sounds out of it. i redid the timing chain and still nothing. and a weird thing is that i had the motor runing before and now it wont run.

thanks for any help

 

Back off the rocker adjustments and try it again.

Were the valves reworked?

 

the heads were rebuilt totally by a machine shop