when they'd let off the gas, the motor would start winding down w/ the dyno, but it would blow a puff of blue smoke right after wot-0 throttle. I know it's burning oil, but what would cause this??

 

Could be sucking oil down the valve guides. Maybe some new valve seals are in order.

When the engine is winding down from high rpms and closed throttle, vacuum is at it's highest.

 

thanks rob, can you think of anything else? heads were new.. well, think he had about 2-4k on them.

Intake gasket leak? wouldn't that show up at idle? think it would hurt the #s that bad?

 

When you drop the throttle blad there is high pressure there, but not in the crank case, so any weakness (such as the breather tube to the pass valvecover) will suck in crankcase air. Usually its the breather, but rings could cause this, but if it only does it then there is nothing to worry about.