BKbroiler

I finally got my 77 back on the road. I had Bair's rebuild the rear and change from 3.08 to 3.73. As I was reinstalling, I also changed all u joints to Spicer solid units. Drove it today. No gear whining at all. I also changed the speedo gear and that seems to be OK too. I tried one launch. More wheelspin than before but the car does accelerate quicker. On the highway, it seems like the trans is still in second, but I can live with that. I will be trying it at the drag strip in a few weeks and I'll let you guys know what happens.

redwingvette

Sounds good. Next you wil be looking for an OD trans :lol: :cheers:

BKbroiler

My long term plan is the 200 4R which I see you have. Some day.

cardo0

Congrats BK. :cheers: Now that you have our attention you must give us a report from the drag strip. :yesnod:

Bob Turner

BKbroiler,

Congrats! I also changed over to 3.70's a couple weeks ago. Haven't gone for a drive yet. Waiting on 22 tooth speedo gear change (this week). I can't wait to light them up!! Should be a big difference.

Bob :cool:

74 vert

:cool: , I often wondered about a gear change. Get her on the track and post results against some of your prior runs. :yesnod: :yesnod:

BKbroiler

Bob Turner - I see you're using the Richmond trans, so maybe this doesn't apply, but I had the red 21 tooth gear in my TH350. I changed to the 25 tooth white gear (20% change), and the speedometer is close now, maybe slightly slow. I might try a 24 tooth gear.

Cali,68,L-79

You'll enjoy the increased seat of the pants acceleration (I have 370's). The highway RPMS get to you on long trips but there's drawbacks to every swap. Enjoy!!

:cheers:

American Boy

For the speedo gear, try this site, http://www.bgsoflex.com/speedo1.html . I use it and it worked. You must know the number of teeth on the drive gear though. (inside the transmission).

Stephan

Bob Turner

BKbroiler-

Excellent point- Changing from 3.08 to 3.70 is a 20% change.... I will buy three speedo gears- 22, 23, and 24 teeth gears. I will start off with the 23 and see how it is and then I can go up or down... Thanks...

Bob :cheers:

BSeery

I went from 3.08's to 3.73 and wish I would have gone to 3.55 / 3.42's. I have horrible traction problems with the low first gear in the 700R4 and running about 3K rpm at 80-85 mph.

jbroughton

Stephan, that's a nice calculator for the speedo gear. I don't see the number he refers to on the face of the speedometer, so I just used 1000. Anybody have any idea if that is correct for our cars? Also, I thought I saw in another post that the number of teeth on the drive gear was 8. Is that the same on all of the Muncies?

Thanks!
Jeff

Glensgages

Been-there/done-that...
15.704/86 with stock 2.87s (July '02);
15.003/91 with 3.73s (Nov '03)...
Combined w/ 3.06:1 1st Gear ratio, traction is now a problem, even with a stock Cross-Fire...will use sticky 26" street tires in future testing
The '82 doesn't 'pull' the last 250', I'm guessing the stock CFI fuel-pump is faulty...'85 pump is next on list

Jersey8t2

How hard of a job was it to change out your rear. I'm thinking of doing my own also? I have a 72 auto, with stock 3.08's

bs82vette

No break-in procedure with your gearset?
See RandysRing&Pinion.com for detailed break-in procedure for new gears.

Gordonm

Not to bad of a job at all. Just takes some wrenching and some elbow grease. It will save you quite a bit of manoy if you deliver the pumpkin to a shop instead of them taking it out. I have had mine out many times.

BKbroiler

I agree with Gordonm, not too difficult at all. Probably the worst part is removing and replacing the drive and half shafts. The onle tricky part is pulling down the rear crossmember. EdT on the forum showed me some pics using a large gear puller. Worked like a charm.

As for break-in of the rebuilt rear, Bair's recommended a couple 10 mile drives with cool downs. I did that, then gave it a little abuse.

Jersey8t2

Did you ever think about 3.55's to your 373's? I'm still not sure which one I'll go with. Is there much of a difference?

battsup

I have 3.73's but i wish i had 3.55's or 3.42s. Spinnning my tires doesnt turn my crank, plus its just added cost on tread life and annoying because of the decrease in fuel economy and high rpms on the highway.

BKbroiler

There would be about a 5% difference. Cruising at 3150 rpm with 3.73s would put at the same speed as 3000 rpm with 3.55s. Eventually I will put in an overdrive automatic so I wanted as much gear as I could tolerate for now.