The most I ever ran for rpms was 4500 in 5th with 2.73's and 215/60/15's. I figured it was like 145-150 on radar but if you do the math it should have been 160+ or something. The math doesn't account for drag, load, resistance,etc......This was a slight down grade with a at the time mostly stock 87GT.
, been there a few times without any problems though.