1965 barracuda rear rear end?

Jack up the rear end and spin one tire. If the other side spins the same direction it's a sure grip. If it turns the opposite direction it's an open rear end. I agree with 65cudalover, the 7.25 is not the strongest rear end for aggressive launching. If you do much more of that you will need to consider an upgrade. I have a narrowed 8.75 in my '65 Barracuda. BTW, when narrowing the rear end we calculated the dimensions to center the wheel in the wheel well. I can fit a 12" tire in there now with no tubbing.