Well, I have test fit magnum exhaust manifolds on my 65 273 and my 87 318, had to grind the head a bit on the 87 where the rear most air injection port is and needed to plug the air injection ports, but they fit. I'd venture to say they'd fit the other way as long as you do not have exhaust manifolds with air injection ports. since those will not be covered.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.