833 Advice Needed

With your final drive ratio being what it is based on rear gear (compounded alot if your running a tall tire ie 27" or taller), I have to ask a few more questions, tire diameter? and at what speed are you placing it into overdrive? I am guessing the reason it feels like it is "powerless" is because you most likely are not in the power band for whatever engine your running (that would also help with diagnosis, engine size, mods, intake and carb combo, cam specs, etc) but it really does sound to me like your lugging the engine, which would cause a lilttle noisy in the tranny also ( I had a very simialar set-up in a 73 Satelite but with 3.23's, ran it in the quarter and only used 1st and second gear, 3rd was great up to 125/130 on open highway, then could shift to fourth and bring the rpms down to maintain that speed) I would suggest a change of ring gear to something more along the lines of a 3.91/4.11 range and it should work much better. What you have isn't really a 4 speed, it is a 3 speed with an overdrive gear ratio in place of what used to be 3 gear and a slight change to how the linkage attaches to cause 4th and 3rd shifter positions to switch around. It's a good combo when set-up correctly. But tire height (diameter) and rear gear are important and must place the rpms in the correct range for a given engine set-up.