New Ring and pinion for 741 case

[Deans68plym]

Can anyone help me find a shop that can cut me some new gears in the 2:10 range for a 741 case. I have a `68 Satellite Sport Wagon with a 4BT/727, and now top speed is about 65 @ 2200 with 2:76 gears and 28" tires.
I want to cruise at about 65 at 1700rpm. to get there with the 2:76`s, I would need 35' tires. Waaaay too much tire on a car.
Any help will be appreciated.
Thanks.

 

[daredevil]

i thought 2.76 was as high a ratio as was offered. overdrive may be the only option

 

[Deans68plym]

Yeah, you`re right. That`s why I`m looking for a shop with the capabilities to cut custom ring and pinion gears.

 

[69 Runner]

Unless your motor is in the torque band at 1700 you will get worse mileage with your 2.1 gear than with the 2.76

 

[Deans68plym]

The Cummins has loads of torque at 1700.

I was told today that Mopar made a 2:40 for the 8.75, but it is very scarce.
Know anything about that?

 

[69 Runner]

You have a Cummins in your wagon?

 

[Deans68plym]

Yeah, a 3.9 4cyl turbo`d Cummins. More commonly known as a 4BT. Hooked to a torqueflite. The "sweet spot" to run the 4BT is 1700 to 1800rpm.

 

[69 Runner]

really.:edgy:

Now we need PICS!!!!!!!!!!!:grin:

 

[Deans68plym]

Have some, but my computer has had problems with downloading off the camera since a meltdown last Summer. I`ll keep trying.
But not really too bad to tackle this, I did it all at home.
Engine came from a potato chip step van, and adapter plate, flywheel,convertor,trans, and starter was with a 5.9 12 valve Cummins.

 

[moparstuart]

wow yess we have to see pictures of this thing

 

[Meep-Meep]

You might end up with clearance problems trying to fit the bigger pinion into the case, or the ring gear flange on the carrier may not be in the correct position. I don't know for sure, but something to look into. Why not a 2.94 and a 518 overdrive? That gives you 2.02:1. Or a Ford 9" with 3.0's and the same .69 OD will give you 2.07:1. I think some late model GM rear ends had 2.29 and 2.56:1. Only problem there is you will most likely break it!! Yet another possibility is to go quick change http://www.1speedway.com/Quick_Changes.htm

Oh yeah, and I want to see pictures too!!!

 

[Deans68plym]

Hopefully pics can come soon, busy at work now. But I can see this catching on with the 30+MPG I get with it and can still pull a trailer.
Getting to my gear search, I wondered about pinion clearance also, but who do I ask?
I am keeping this car on a low budget so the OD trans is out. Anyway, I am limited to transmissions that will bolt directly to the Cummins/Mopar adapter. Because of the large Cummins starter, the bellhousing is different.

And NO GM or Ford rearend`s.
Right now I`m using the 2:76`s with 265/70 17`s, and I`m close to where I want to be. Around 60@1850, but not there yet. Believe it or not, the tires look good on this car.
Who can make me the gears I want, if they are feasable?

 

[69HEMICORONETR/TCONV]

Congrats ! you own the only 68 Sport Satellite Wagon with a 4BT ! ...........I want to see pictures !

 

[Deans68plym]

Thank you, but please no applause, just throw MONEY!!
I had a couple good excuses, the 318 was tired, and the car will be pulling a trailer in Spring, so it needed more motor.

But come on, someone please find me a good tool and die co. with the tools to try to make me some gears! I`ll settle for 2.5s.
The pics will show you an original paint, rust free,original int. car I scored on E-Bay last June for $2500 from Arizona, with a somewhat out-of-place looking engine. What pics won`t show, I can only say is, it can all be done easily in your shop in 40 to 60 hours .
Find a good 4BT first, then worry about the rest.

 

[rumblefish360]

Whats your mileage now. I say no way for 30 mpg's in a heavy car, but, best of luck and go for it.

 

[Meep-Meep]

There is US Gear, Motive Gear, and a ton of Chinese manufacturers. Yukon is Chinese I think. Most of these gear companies only deal with the 742 and 489 case stuff. You might be SOL not only on the ratio but on the 741.

One company I have dealt with in my neck of the woods is West Coast Differential. I have had great service from them and they seem very knowledgeable http://www.differentials.com/

 

[Deans68plym]

I`ll look into the West Coast Diff.
I have no problem changing to a 742 or 489 case if that will help in the gear search.
Thanks.

 

[Deans68plym]

 

[69 Runner]

pretty interesting

 

[Deans68plym]

I`m running it as is `till next winter, then I`ll pull the eng/trans for paint and detailing under hood.
Real smooth down the road, and it doesn`t really care if it`s going uphill or level road.