You are correct Jay! With 2 and 1/4 headers, the 508 bellows when the twin 750s open up!
It's a mellow rumble with the caps on, flowing through the 3" exhaust. We were liberal with the sound deadener in the cab, since back when it was a bracket truck, and gutted inside, the cab acted like a resonating chamber!
"Livin' in a powder keg and givin' off sparks"
4 Street cars, 5 Race engines
