Moparts Tech Archive

Automatic Trans.

GearVendors OD installed in '73 b-body

On my never ending quest to create the "ultimate" Street Machine I decided to add a GV OD unit.
Following is a short installation report:

The packagae arrived approx. 10 days after I placed the order with GV.

I started to disassemble the MeanMachine. Due to the second crossmember for the torsion bars on 73 b-bodys I decided to use the opportunity and replace the lower control arm bushings as well. I started off with removing the frt wheels, discs, spindles, torsion bars, torsion bar crossmember and tranny crossmember. Then I removed the tail shaft housing.

Unfortunately, GV send me the wrong adapter, the support bearing ID did not fit the 727 out put shaft. I called GV and they shipped the right piece right away

The adapter in the middle of the picture is the correct one for the passenger car 727!

I installed the adapter, adjusted the coupler end play as discribed in the GV manual

and mocked everything up for the first time.

There was some severe interferance with the tunnel

which I tried to solve with

but I soon realized I won't be able to make enough room this way.
I decided to cut the tunnel and fabricate new sheet metal in order to provide sufficient clearance.

Side piece fabrication (I love hand work! ):

Side pieces welded into place:

Then I covered everything with a piece of sheet metal:

I used zink primer befor welding. After the welding was complete I primed, sealed and painted the modifications:

The OD unit got reinstalled to the transmission and the tranny crossmember went back into place

During the installation of the parking brake cable I found the cable rubbing the OD case.

I added a second "hook" set up to keep the cable away from the Overdrive

Time to hook up the electric and install the control unit, dash switch and manual switch. The control unit found place on top of the parking brake mechanism, the manual switch is installed right beside the high beam switch.

I had the drive shaft shortened at a local drive shaft shop and specified 36.5" from center to center. Unfortunately, they cut it to 36" and I am not really happy with the slip yoke engagement

Of course the exhaust didn't fit anymore and I had some new collectors (5" longer then the originals) made locally:

To compensate the longer collectors I cut 4" off the end of the H-Pipe, another inch off the muffler flange. This way I was able to move the crossover of the H-Pipe behind the OD unit.

After a successful mock up I removed the exhaust system again and painted it with high temp paint

Today the final assembly took place and the first test drive went flawless. The OD works geat and gives me a final drive ratio of 2.76 with my 3.55 geard rear end. The OD gives a very postive shift and the control unit set up suits the torque caracteristic of my engine perfectly.
The entire modification cost me $2335 for the OD unit, $130 for the drive shaft mods, $80 for the custom made collectors and some 30 buck on miscelaneous materials.
Its well worths doing it if a true street car is in your mind but be aware it is not a simple bolt on modification on 73-74 b-bodies!
Here are some shots of the finished car:

Frank - The_Mean_Machine

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