The head gasket only crushes about .005...Just lay on the head and snug up a few bolts,all that's needed,gasket is still good to go.
I just started my 261 build a few weeks ago and I used 10-30 Comp Cams break in oil.This engine has forged pistons,bearings,.005 wall clearance , .002 on rods and .025 on the mains.Oil pressure is fine,pistons are quiet...Once it gets a few hundred miles I'll use a slightly heavier oil.
