Thread: Rearend and axle selection

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Hi all
I'm looking for some opinions and guidance on what type of rearend and gear ratio to put into my 37 ply. I'm putting in a 97 Trans Am LT1 a little over 300hp with a 4L60e tranny. The car will be a cruiser and used on the highway more than the drags. Like to hear your thoughts.

Sorry, we've banned all members from Pittsburgh until the Steelers win another Superbowl. (Guess where I am from originally? )

Welcome to the forum. Your gear ratio depends a lot on rear tire height too. The fact you are running an overdrive tranny makes it much nicer. I would think a nice cruising gear would be somewhere around 3:50 with the overdrive. If it were a 3 speed, I would say more like 3:00.

What part of Pgh are you from?


Don

Lots of chagnes for the Steelers. Just hoping they are the right ones.
I'm originally from the south hills Whitehall area and now I'm out near the Greater Pitt airport, North Fayette. Thanks for the the gear ratio answer. My tranny is with overdrive. I see you have or had a dodge. Any suggestions on what kind of rear end to put in my 37 Ply eventhough I'm running a GM powertrain.

Yep. 9" Ford.

8" or 9" IMO

If you're not going drag racing just an 8" should do fine. If you could locate one out of a Maverick, the length should be very close for your coupe!!!!!! With the OD, you could easily get into the 3.70 range and still have decent RPM on the highway.... 3.25's or 3.50's with the od should really let the car loaf down the highway at normal cruise speeds. With $3.00 guess prices here next month, might be a really good way to go...

A 4L60E trans has a .70 overdrive, so with a 3.25 gear and a 28" tall tire, you would be cruising at 73 MPH @ 2000 RPM.

I;ve heard that the 8.8 is a good one now days . If i remember they have 31 spline axles in them , have less drag then a 9 and handle more power then a 8 in . Can anyone verify this when i mentioned putting the 9 in the rod this is what a couple guys where telling me . Of course you will have to have one narrowed maybe .

The 8.8's are a rugged unit, heck the Mustang crowd is running in the 10's with them and do little changing other then aftermarket axle and a spool. A spool IMO is worthless on the street, a good posi unit would be a much better deal.... I came up with one of the 8.8 IRS units out of a T-Bird, it may wind up in the Ranchero. Only drawback being the half shafts, they break a lot easier then a one piece axle....

For a cruiser, I wouldn't hesitate to put in an 8.8.

That's the same trans I have in my truck. With 3.73 gears and 31" tires it cruises @ 2100 rpm @ 75mph.