There is a local guy who is pushing (i kid you not) 980 out of a 393 stroker in a factory "mexican" 351 block. Has been for 7 months now. The block is girdled on the bottom end and he runs race gas with a conservative A/F Ratio and a ridiculously gorgeous twin turbo setup. You can easily make 600hp on 351 blocks and have them lead happy lives but like ANY MOTOR IN THE WORLD...its all in the tune and avoiding detonation.