68 Charger, 440 with 484 cam, 4.10's and the Keisler 5spd. It was a pain to get right in the car and the thing shifts clunkier than a Getrag hooked to a cummins. It's also too much OD for the cam. In retrospect I really wish we had just put a Passion 4spdOD in it.
Sounds like you may have one of the earlier Keisler kits, you really need to remove some of the webbing on the transmission case that interferes with the floor crossmember, use a 4 spd hump, to get the transmission up into the tunnel to correct the driveline angle, and if you have a first generation shift tower, you need to upgrade to a 3rd gen tower for better shifting
I run a Keisler TKO 5spd .64 OD behind my 70 Charger 440 6 pack/450 HP, Dana 60 4:10, 27" tire, cam is a .470 with 1:6 rocker so in essence it's .520 lift and pulls fine in all gears, OD cruise RPM's are ideal for my set up, could be your cams duration that's killing your OD RPM's, one of the reasons I went with a smaller cam for shorter duration, but increased the lift with 1.6 ratio rockers
