86’ is almost ready- almost

I have come to (near end) of my quest... I have redone the floor; Stringersm, foam, and even added decking, timing has been set, cap and all internals done. I DIDNT KNOW NOT to be running it out of water!!! from the get go the prop has turned when running (fast) and now that i have put her in water, she is slow to engage in forward and doesnt in reverse... I have searched the forum, what's wrong, there is also an "unbalance" to the rotation of the drive shaft that even "thumps" at certain RPM. HELP.

If it does not engage at all in reverse it sounds like yu screwed your tranny. It probably got overheated running those speeds without much cooling.

With the tranny linkage hooked up check and see if it tries to move when the motor is off and you try to put it into reverse. It may try to move but the cables could be really stiff and need replaced/lubed. If it has full movement then you definately have internal problems with your tranny, prolly fried the reverse clutch pack.