Cascade Crew

1987_sportcoupe · Posted: Sat Oct 01, 2011 1:18 pm Post subject: Drum to disk swap

So I want to swap out my old 2:73 drum brake rear end for a 3:42 disk rear. My question is 1, where can I get a good used one? And 2, what else needs to be swapped other than the rear end?

aaron_sK · Posted: Sat Oct 01, 2011 6:40 pm Post subject:

Tumwater still has a niner out there IIRC.

Need to change the prop valve under the hood.

Best of luck finding a factory 3.4x with disks. I'd start with the 3.2x that you'll readily find from the higher-performance V8 cars.

Out of curiosity, how have you arrived at the conclusion that you have 2.73's now? GM was very generous with the gearing on the V6 cars. My super-base Sport Coupe had 3.42's in it, for instance.

Alphius · Posted: Sat Oct 01, 2011 6:57 pm Post subject:

LG4 cars came with 2.73 in '87, but the SC seems like it was V6 only in that year, and both auto/stick came with 3.42 with the V6.

3.42 makes the car feel fast enough. That was why it came with that gearing with a V6, cause it didn't have the torque that the V8s made to turn lower gears.

Al Hasse · Posted: Sat Oct 01, 2011 7:00 pm Post subject:

aaron_sK · Posted: Sat Oct 01, 2011 7:00 pm Post subject:

He has a six, Gabe. I've seen the car. That's why I'm curious what made him think he had 2.73's.

You are correct about Chevy's reasoning. Same reason they put the 4.03 first gear in the V6 T5's. Makes a crap-ass car do a hell of a brody. Wink

Alphius · Posted: Sat Oct 01, 2011 7:39 pm Post subject:

Torque multiplication on T5/V6 car with 3.42: 11.00
Torque multiplication on LG4/700R4 with 2.73: 8.35

Effective torque at wheels in first gear:
V6/T5: 1760
LG4/700R4: 2045

I thought the V6 would be closer, but this does help illustrate why the ridiculous gears are even there.

He probably does have 3.42, you are correct. Smile

91RSVert · Posted: Sun Oct 02, 2011 4:41 am Post subject:

My old 91 v6 had 2.73's in it. No clue why, but it was suppose to have 3.42's.

I lucked out and found a posi, 3.42, disc from a 92 firebird or ta and tossed into mine. I had to order new ebrake cables because they were damaged during removal. I had already changed the prop valve.

I think later installed a new rubber hose from body to axle. I would suggest doing that while its all out.

Alphius · Posted: Sun Oct 02, 2011 8:22 am Post subject:

Some people just throw whatever in there if the old axle breaks or something.

2.73 on a V6 would probably feel pretty dog slow. Smile

1987_sportcoupe · Posted: Sun Oct 02, 2011 11:04 am Post subject:

I'm not positive that I have 2:73's its justwhati was told. Either way I want to go disk brake posi rear end. 3:23 would be fine for now. And how much do they want for them at tumwater?

aaron_sK · Posted: Sun Oct 02, 2011 11:14 am Post subject:

$160

http://www.pickapartolympia.com/price-list/

If you want it hauled up here I can do it for diesel fuel.

Go look in your glovebox and write down all the three digit codes that start with the letter 'G'.

1987_sportcoupe · Posted: Sun Oct 02, 2011 11:23 am Post subject:

Alright I don't get payed till the 15th so I wouldn't have the money till then. Hopefully they're still there

RSFreak · Posted: Sun Oct 02, 2011 11:28 am Post subject:

aaron_sK · Posted: Sun Oct 02, 2011 12:45 pm Post subject:

You know I think about it now John and I am not sure they still had it out there when we went to pick up the hatch last week. It was in a white car, correct?

jchaussee · Member Joined: 14 Nov 2010 Posts: 1318 Location: renton

I saw on on cl off a 4th gen firebird. Dude wanted cash . Could prob get it for 100 bucks

RSFreak · Posted: Sun Oct 02, 2011 9:22 pm Post subject: