I am new at this, proud to join the ranks of GTO owners, recently bought a 68GTO ragtop, and I am afraid to say this to a bunch of poncho guys but it has an Oldsmobile W30 455 in it (I believe 1971). I am thinking that eventually I will go back to a correct motor for the car. I was told tat the motor has 5K in rebuild and performance modifications. The seller said he did not know the details on the internal modifications. I can see it has a 750 CFM Edelbrock, Edelbrock Torker 55 intake, headers and 3” flowmaster exhaust. It is close to being finished. I would like to know what you guys think of the combination and gestimated horse power/torque.