Opinions needed on my rear end

[olds307 and 403]

Awesome, what gear ratio did you go with?

 

[Mike T]

OK so this is gonna sound a little "out there" but it happened to me about 15 years ago. I had a 68 Camero hard top with a respectable 355/ Muncie T21(?) in it. Changed the clutch after having it for about a year and when I put it back on the road, it would get this little vibration that started at exactly 58 mph. Go faster, get worse. Didn't have the problem before the clutch. I, like you, checked everything I could think of without ever finding anything. In desperation, I decided to change the clutch again, hoping that it would solve the problem. When I started to unbolt the u-joints at the back of the drive shaft I found that one side was tightened more than the other. Neither side was loose but they were not tightened the same. More because I was tired of laying on my back under the car that day than thinking it was the problem, I loosened both sides, tightened them evenly and went for a ride. Could not believe it!! No vibration!!

I'm not suggesting that this is your problem but your problem could be something that you think is done correctly but isn't.

One other thought. If you are racing the car and leaving the line real hard, you might want to be sure that the pinion is tightened down hard against the crush sleeve (or spacer). It's not impossible that leaving hard enough times hasn't created a couple of thousandths "extra" slack. Good luck.

 

[marcar1993]

olds307 and 403 4.10's, just like I had in the 8.8, but no issues like the 8.8 gave me. I did consider 4.30's, and I might regret not doing it, but I could always regear down the line

Mike T Thanks, but it was the 8.8, the dana 60 fixed it. Probably a bearing issue, but its a moot point now.

 

[Mike T]

I'm glad. Now go raise hell with the Dana.

 

[michmalibuman]

View attachment 77217 View attachment 77218
I fought through what seemed like never ending issues with mine. It’s going back together with a Quick Performance Ford 9” with 3:70’s, Eaton Tru Trac and Moser axles View attachment 77217 LS 6L80e powered) and I am never going to work on it again...

Ace Burt, I think you hit the nail on the head. Would you order anything different ? Like 410 or 390 gears.

 

[Ace Burt]

Ace Burt, I think you hit the nail on the head. Would you order anything different ? Like 410 or 390 gears.

No, I wouldn’t change anything. I have a 6 speed automatic so I can run a bit steeper gearing without having to scream it down the hiway. My only advice to anyone is carefully weigh all your final drive numbers to make sure the car runs the way you really want it to.