Thanks, I assumed they were New GM rods and crank but I will have to check that . Sorry about the thread ,I just copy and pasted existing paragraph that was sent to me before I bought the car. I appreciate your response ,great information, again thank you.Wow this appears to be a photo or something, takes a few tricks to make it viewable.
This is classic build with preSMOG factory parts. The GM rods are the weak link in this, they and the heads would not be on the list of a fresh build today. The rods because of fatigue issues and ultimate strength they being only forged mild steel where today even the inexpensive hot rod rods are alloy steel like 4340 or 5140 steels which start where the pink rod peaks. The bolt material counts for a lot most instant rod failures start with the bolts stretching which deforms the cap allowing it to push the bearing inset at the parting edge into the oil clearance which squeegees away the lubrication, things get hot the insert welds to the shaft and spins till the hole mess seizes and the rod busts. Stock rods can benefit from being resized to insure the cap to shank contact area is wide, parallel and flat as possible then ARP 8620 steel bolts are used to clamp it all together. Then shank polishing of the rod is accomplished followed by shot peering. This removes stress concentrations and the shot peen restores the compressive layer of the forging process which greatly improves fatigue resistance. This is the stuff you need to know about dropping shop names does not mean they did these things, this is stuff your father would have paid for or not and should be on the invoices. Barring that you would need to talk to the shops to see if they have records or memory. Not knowing I’d limit RPM excursions to 6000 and that seldom.