340 or 360?

The 360 has one claim to fame the 340 never achieved, and that was being the engine that powered the quickest american production vehicle in 1978 in a pickup truck.
I could be wrong but wasn't the X block that Glidden used to win pro stock in 79 based off a reinforced 318 block, I know they came with a 318 bore(3.91) from the factory and according to Mopar at the time could only except .150 over bore to 4.06 bore.