engine knock

damned said:

I've got a 78 king cobra with a 302... 725 Demon carb ...Victor heads and who knows what else.
My problem is I get an engine knock only when the engine is hot and under a load or higher rpm.I have noticed the oil pressure is a little low but will come up when you hit the accelerater. Hoping it is something easy and cheap (kinda like me) Let me know what you think.
thx

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If you have already checked all exhaust components for gasket leaks and de-torqued bolts........AND because you note it occurs under load I'm going with rod knock. Have you scoped the engine? You will be able to figure out which piston is affected with a decent scope.

Does it also have a "back rattle" as the RPM load comes down anywhere between 2500 -3500 RPMS?

You can salvage it before it shears bearing material to the extent it will "double knock" - once on the piston and again on the crankshaft journal. Since you indicate you have low oil pressure, I'll bank that the journal is already affected.

How cheap depends on the extent of the damage. These sounds are really hard to diagnose, but based on what you said it does not sound like valve issues or exhaust rattles.

As mentioned check the exhaust gaskets, My header leak sounded just like a rod knock, it got worse when the car was under load.

If your timing is too far advanced it can knock or just cheap gas.

Mine only drinks 93 octane. I run my timing at 6 degrees before top center.

Also I have heard a cracked flex plate sound like a rod knock. I would think this would show up even cold.