putting my lt1 back together now. its got 11.1 compresion
306cc cam lunati 1.5 roller rockers hardend pushrods crane
dual coil valvesprings for 600" lift with homeported heads,
and crane roller lifters

i dont wanna run into valve float would ferra valves be the
best and what rpms could i run this to before losing power
or getting valve float?

 

That's like asking if a painted engine will add more HP.

Valve float is weak spring pressure when the valve is closed. If the spring pressure is too weak, then the closing valve will bounce when it comes down on the seat.

At what rpm the valves will float depends mostly on the valve springs but also on cam profile design. If the cam slams the valve open then quickly allows it to slam shut, a set of springs could be worn out in less than a year. (Comp eliminator camshafts).

If the valve springs match the camshaft then valve float is whatever is printed on the cam card.

Valve springs are not the only factor in maximum lift. The valve guides must be cut down also so that the bottom of the spring retainer doesn't hit the top of the guides.