Originally Posted by 69NMYSS
Not sure if the GT500, stock, is putting down 620rwhp on a Mustang Dyno? Regardless, the additional HP coming from the GT500 (stock) cost you $5k more than the ZL1 (Stock). $5k can get you a lot of HP with proper cooling on the ZL1.
I agree the GT500 stock is not putting down 620 rwhp, it is make 662 hp at the block which compares to the ZL1's 580 hp at the block. 620 rwhp would be close to 745 hp at the block - do not think so at all!