Yeah I know the 7.5 rear end is crap thats why I am not bothering to race my 99 for now just built up the 80 for that.I suck at racing with my six speed anyway.
I hear you on the gears thing and really wasn't going to go any higher than 3.42 anyway but may stay with 3.23 or even 3.08..just as long as don't have under 3 gears in the car..and the turbo 400 is for sure on my to do list..

 

Well I just had my tranny re-built like 300 miles ago, and it whines pretty loud. Its a saginaw 4 spd ( I know I know, just SHh about the sag ) I run it hard too, and also has seen 4 times at the track, still shifs fine. Is this normal since they replaced a gear inside it? I just dont want to be cruising down the road and I have no transmission. Never noticed a whine b4 I got it re-built either.

 

Well, this thread has been primarily about rear-end gears, but trannies will whine too. That's normal though. The Muncie M22 "Rockcrusher" got it's name from its loudness. It was because the gears were more straight cut, which makes them louder. I wouldn't worry about it though. The tranny in my '92 Z-71 whines a little (manual), but that's completely normal.

Oh, 80TA, I think earlier you were saying you didn't know the current ratio of your rear end. Well, here's a simple formula to help you figure it out. It won't be exact of course, but it will get you close.

Gear ratio = (RPM x tire diameter) / (MPH x 336)

You can get your tire diameter by doing the math of it's size, but to be more accurate go outside with a ruler and measure your tire height. This ratio also assumes you're in direct drive (3rd gear for your auto). And unless you have a lock-up convertor, your rear end ratio will also come out to be a little lower (numerically higher) than what it really is, since autos without lockups will always have some slippage in them. Anyway, hope this helps. Good luck.

 

problem is not sure my speedo is accurate..pretty sure its out and it doesn't even work consistently putting in new cable today hopefullly.The former owner swapped in my pontiac 400 and I think different tranny..and pretty sure the speed gears are whacked out.Going to take off cover and change gear oil next week so will find out for sure what the gears are.It does seem pretty imprecise to guess since like you said non lockup torque converters slip.I would be willing to be I have 3.08 or some 2 series gears.