Your not going to see much oil pressure if any oil pressure on the gauge cranking it over. The starter wont turn it over fast enough. Just pull your coil packs, and turn it over for 15-20 sec. Then plug your coil packs back in and fire it up. Your lifters may tap for just a sec until they prime up. You should see oil pressure in a sec or two on the gauge. If the motor was assembled correctly you should have enough assembly lube to no hurt any bearings.
91 RCSB-- Forged LS7 bottom end, ported LS3 heads, ported LS3 intake, custom EPS cam and a 4l80e.