The best and biggest thing I found on switching from a solid flat tappet cam to a solid roller cam with similar or the same lift and duration was the roller cams all had a lot more piston to valve clearances from 20 BTDC to 30 ATDC thumbs
The lobe designs help the motor make more power shruggy

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