Straight Pipes

805moparkid said

but with open headers you do want to let the motor run for a minute after a run as to not suck cool air and crack a valve or seat, but thats with open headers, no exh

Click to expand...

This is an old wive's tale, look at some tractor, aircraft engines, nearly no exhaust at all.

The Rolls such as Merlin/ Griffin and Allison V12 aircraft engines are a good example

I don't see any exhaust system, do you?