I think your best bet would just be to convert to solids. For this purpose just disregard the fact you're using a 4k head and source the parts for a normal 5k solid conversion. This is essentially my setup - 5k bottom end, 3kbp head, chev lifters and A12 pushrods.
I reckon if you tried to use the 5k hydro lifts, pushrods and non-adjust rocker gear then your pushrods might pull up slightly short, but don't quote me on that.
If its a 5k bottom end, then just use a 5k head gasket. :jamie: Reccomend genuine.