"safe RPM "
I couldn't kill the engine in my old car.... stock non filled RB block, stock forged 440 crank welded and stroked to 4.15, stock LY rods, LIGHT Ross pistons and pins, ARP main studs with stock caps, stock oiling. this was the basement for my mild ported Stage VI heads and Ultradyne NF69 mech cam shaft. Had the shift light set at 5600, trapped at 6200, best of 10.18 in Vegas and ran 9.93's on a string in Bakersfield. Had some signs of cap walk everytime we tore it down, but not as bad as most I'd seen. Kept timing below 36 degrees.