Hi Everyone,

I am contemplating the upgrade of the gears in my 87 Trans Am. It currently has the 9 Bolt Australian Rear End in it.

I currently have the stock 3.45 gears in there. My car has been upgraded to the LT1/T56 Combo that is why I am posting in here.


I am contemplating between the following gear ratios, 3.73, 3.89, 3.91.

I am unable to goto a 4.10 cause in the 9 bolt there are less teeth in the pinion on the 4.10. It would also increase the chance of failure.

So between the three listed above, what am I going to notice. Are 3.73 adequate? I want to get to the point where I make some gains on the track and get into more of a comfort zone to make 6th gear effective.

Any input would be greatly appreciated.

Thanks,
Scott