!-7/8" was better. Both of them were the step design. TTi says the 1-7/8" step is recommended for above 500 HP, and the 1-7/8 long tube for over 550 HP. My engine maxed at 568 HP because I didn't want any pinging on 91 octane and I didn't want it to lope at idle. Ported Eddy heads flowed 308 at 0.500. Torque is over 500 ft-lbs from 3,000 to 6,000.
