Need A Little help Please

I'm far from a cam expert but you say that you can feel it come on or start pulling........More stall or less duration.

If your losing 60' times and, losing time after each shift........it's going to run slower......than expected.

If it feels like a 2-stroke and you know when it comes on the pipe.......That's probably the rpm you want your stall.......at least.
Or a cam that will come on much sooner to take advantage of your 5000 stall

Then settle in on a rear gear ratio.
lower gears will help.......but it's more like a band aid.