Quote:

The motor is in a challenger TA, 340 six pack. I wanted the engine put back to stock. The rebuilder told me that "stock" was pretty close to 10:5-1. Just wanted to make sure that this motor would be fine on pump gas and not be harmful to the engine.



Pretty close to huh? How close did he get it? You might be worrying for no reason.

So, what compression was the engine really built to and how was the compression ratio determined. Have him explain how he got 10.5:1. Deck height, piston type (part #, valve relief cc's) cylinder head cc volume, gasket thickness, bore and stroke?