Im just saying my truck had a 383 stroker with Comp. Magnum 280 hydraulic cam, headers, 1 step above stock converter, and 4.10 gears. Edelbrock RPM Performer Air Gap with a 600 Holley and a 1" spacer. I pulled the spacer off at the track and picked up e.t. 1.5 tenths and backed it up 4 passes in a row. i was shifting at 5000. Now I'm sure if my setup was capable of 6500 or 7000 it may have helped. Years ago I had a 525 horse stroker with Victor and 850 double pumper shifting at 7700 and that car was faster without the spacer to.