8 3/4 Sure Grip ratio change

Great point 68. I have a 417 stroker it is pretty tourqey. However it shifts around 3400 rpm or so even under full throttle. I want to make sure:

1. the 3.91 gears are compatible with a 417 stroker and

2. the 3.91 will hold revs longer into the upper end of the rev range.

NOt sure if it's relevant but I have a 2800 RPM stall converter. If the responses to the above are are affirmative the I'll go with the 3.91.