1988 Ford Mustang 5.0 Pro Stock Build - Pro Stock Pony Part 3 - Tech

Once we generated numbers to illustrate the gains offered by the induction upgrade, it was time to see how much power was available with this new combination. Given the tremendous torque numbers being made, we were beginning to get nervous about the strength of the stock block but decided to press on with the project. Since we were effectively out of turbo with the standard 60mm unit (at 550 wheel horsepower), the guys from HP Performance decided it was a good time to perform an upgrade. Out came the 60mm turbo, and in its place went a larger 67mm unit, capable of nearly 100 extra horsepower.

Measured back-to-back at just 10 psi, the larger 67mm turbo increased the power output from 575 hp to 604 hp, though the smaller 60mm turbo was slightly more responsive in the lower rev ranges. Obviously, at elevated boost levels there would be no comparison, as the smaller turbo would continue to sign off, while the power climbed with the freer-flowing 67mm unit. With a bone-stock motor, the clear choice would be the smaller 60mm turbo, but there's a case to be made for the larger 67mm turbo on a modified motor once you get past the 550hp mark. For an honest 600 rwhp, there's no comparison, as the 67mm turbo is the only way to go. With the motor capable of producing a solid 100 more horsepower that it had when we posted high-10s, the question now is, is it capable of dipping into the 9s without splitting that fragile, stock 5.0 block right in half?

The boys from HP Performance promised to take the car to slightly sunnier Phoenix for a shot at the 9s with a stock bottom end. If they're successful, we'll be sure to let you know, but even if the stock block won't stand the abuse, we'd still call Project Pro Stock a smashing success.