5 liter MOPAR

I did some research - apparently the 301 poly was built in 1957 strictly in Plymouths. It had a 3.91 bore like a 318 and a 3.12 stroke as opposed to 3.31 for a 318. This is NOT the same as the 301 made in 1955 for Chrysler cars, which was a poly motor, but one generation earlier.