Intermittent Backfiring After New Head Gaskets

eekvonzipper said
That “good” 1008 Fel-Pro head gasket didn't help matters either.
They're not for a 273...
Pictured here is what a 360 Head Gasket looks like on a 273 block.

View attachment 1716291157

You know I forgot all about that. That'd be enough for me for a tear down and get the right gaskets on it.