okey update!!! So Macjr was able to borrow a digital light and sure enough the tach was reading 2x the rpm because it is a 6k tach, not a 7k tach. The cluster isn't able to distinguish 4cy vs 8cy, so it just assumed it was a 4cy in higher rpms cause read 2x as many sparks from the v8. That being said.. this being my first mustang guess the prev owner swapped in a 4cy tach. Which means the 4k I was shifting at was actually 2-2500rpms. Guess I'm going to enjoy my new found discovery and finally discovering what it feels like to shift at 6k. Yes I know rev limit is about 6250 or so. The issue on the rear end still baffles us. I went to the local pullpart and pickedup a budget 5lug swap - lincoln rotors and ranger axles. Made sure everything was straight and the 28 splines were in great cond. The rotors weren't warped and tomorrow I'm going to meetup with Cavallo. Might buy his 99 17" gt's. Yeah I know the fronts will have to have the center caps removed or I could mash in the dust caps. The front rotors are temp until next month when I can afford sn95 spindles. About the rearend.... I plan on pulling it apart and replacing the bearings, seals, axle shafts, etc. This problem actually gave me a reason to finally do my 5 lug swap. I've come to suspect it is a bent axle shaft because the pssgr side turns fine. But then again might be the bearings too, never actually looked at the shafts themselves when I opened it up... just looked at the gears. Don't think the splines are chewed cause when I org opened the casing, I didn't see any shaving or pieces. It has been making a rubbing/grinding sound with that wobble. Scary but yes I've drove on it a few times, to and from school. You should see the looks on the peoples faces behind me. First they trail gate me, then slow down and drive to about 10 cars lengths behind me waiting for the wheel to fall off. I'll keep you guys posted when I discover the actual culprit. :SNSign: