I've never had a motor that liked to be revved over 7500RPM, I used Valvoline VR10x30 oil in the last race motor that ran 8.86 at 150.+ MPH in my S/P car that weighed 2850 lbs. with me in it, 5.50 at 125 MPF at the local 1/8 mile track in Madras, OR at 2500 ft. elevation.
I use to shift it at 7000 RPM and decided to move the shift RPM up to 7300 RPM at Woodburn, OR (1/4 mile track) and the car ran exactly the same ET but pick up 2.0 MPH in the last 300 ft. 45 minutes after the other run in the morning in time trials: confused:

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)