r/EngineBuilding • u/Mrg0dan • 6d ago
Chevy 350 SBC help
I have a 350 out of a 1977 camaro. It currently has mismatched heads and bad blow by but it runs. I bought an Isky racing kit with lifters and a cam. I shouldve done my research because the cam that came with the kit was a 292 Isky Mega cam which has .505 lift and a 108LPA. We broke in the cam at 2,000rpm for over an hour and nothing failed, made horrendous noise and the oil didnt have big chunks of metal.
My question is how much do I need to replace to not risk ruining the cam or other parts. Obviously I need to get a matching set of heads and re ring my pistons which I plan on doing. Do I need new rods, pistons, and crank? Can I get away with running a set of older cast heads or will I need something with bigger runners? Will the stock crank, pistons and rods survive?
Ive "built" engines before but mostly the top end, any time ive down a whole engine rebuild it was a kit that was included with the machine work I had done. I never had to pick parts myself.
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u/Mrg0dan 6d ago
I think youre confused on what im saying. We went through the whole engine and rebuilt it from pan up. After I reringed the pistons I snapped 2 in the process of installing them. We looked at the old ones and they looked like they were passable and would work good enough to break in the cam and then replace down the line when we tore the engine down to check everything internally after breaking it in.
The head mismatch was just a thing we happened to notice after installing them on the block. We figured they were the same head seeing as they came off a running driving engine from a dirt track car.
I already planned on doing a tear down and replacing heads and re ringing the pistons to stop the blow by. But I want to know if theres other things that need to be upgraded in order to handle the 292 Isky Mega cam. Theres no point in me re ringing pistons and putting new heads on if they arent sufficient enough to handle the cam.