engine GURU qestion....vortec....

[RED71CHEVY]

currently set up:
--12513151 GM crate engine (minuns the heads, i have them and they are for
sell)block modular crank, roller cam, powered rods.\
--electric fuel pump [5-6psi]
--zz4 roller cam lift[.474I, .510E] dura[208I, 221E]
--crane valve kit 10309-1 [good for .550+ lift]
--zz4 take-out 1.5 stamped rocker arms w/ poly locks
--stock push rods that came with the 12513151 [melling mpr373 from
autozone]
--'97 truck vortec heads w/cut down valve boss[height only], new viton seals
--elbrock 1405 no choke
--power wind rpm air gap nock off
--proform hei dist, with vac adv.
--ram horns
--8mm accel wires
--bosch 2 prong plugs
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whew!!!!
ok now that's out of the way, i am having trouble setting the vales, they are noisy like they are not adjusted corretly. they have been re-adjusted [4] time and they still sound the same. are therer any diff in the push rods for a vortec head vs. push rods for ,say 442 fuelie heads if they were on the same block and with all parts listed above [except vale guide plates]. could the stock lifters be not handling the lift/crane spring combo? are they leaking down..?
I AM OPEN FOR ALL IDEAS, SO LETS HEAR THEM.
THANKS FOR THE HELP.