mrbone
Well-Known Member
So, a while back l posed a question about adding OD to a big block 727.
I was asking how many people were running a dedicated OD tranny, verses some of the aftermarket options. I wanted to follow up and give some initial impressions on what I have found.
I decided on Gear Vendors, mainly because a fellow member upgraded my 727 to a reverse manual valve body, with all the goodies. Since I would be running my girl on the strip from time to time I wanted the benefit of the HD 727, rather than upgrading a different OD tranny.
The gear vendors OD came in like three days and had real good instructions. Installation was really no problem. However, you do have to tilt the tranny down slightly. You could 'key-hole' the tranny cross member holes, but I opted to build a new crossmember which took time.
Wiring was a snap, just follow the directions so you understand.
At this point I would like to give you a WARNING; your driveshaft will need to be shortened, measure carefully! Call the boys at Gear Vendors and ask them how to measure. I was told incorrect info OR I didn't understand. They want the driveshaft shortened to the 1/8" so measure precisely.
Of course, on the road it works flawless. The computer lets you run in manual or automatic overdrive. Auto mode shifts for you and manual lets you shift it via a nifty floor switch, which works slick.
I agree with most others, it should have a bit more overdrive gearing. I don't have a lockup converter so I don't see a full 700 RPM drop in overdrive. With my gearing 2750 RPM @ 71 MPH.
Aside from that, it was a very easy install, any good mechanic can do it.
Final thoughts;
Installation is a breeze.
Measure driveshaft "exact".
Key-hole crossmember holes would work fine, if did another- I might do that.
In the end: Nothing like cruising down the interstate 70+ waving at all the classic car fans.

I was asking how many people were running a dedicated OD tranny, verses some of the aftermarket options. I wanted to follow up and give some initial impressions on what I have found.
I decided on Gear Vendors, mainly because a fellow member upgraded my 727 to a reverse manual valve body, with all the goodies. Since I would be running my girl on the strip from time to time I wanted the benefit of the HD 727, rather than upgrading a different OD tranny.
The gear vendors OD came in like three days and had real good instructions. Installation was really no problem. However, you do have to tilt the tranny down slightly. You could 'key-hole' the tranny cross member holes, but I opted to build a new crossmember which took time.
Wiring was a snap, just follow the directions so you understand.
At this point I would like to give you a WARNING; your driveshaft will need to be shortened, measure carefully! Call the boys at Gear Vendors and ask them how to measure. I was told incorrect info OR I didn't understand. They want the driveshaft shortened to the 1/8" so measure precisely.
Of course, on the road it works flawless. The computer lets you run in manual or automatic overdrive. Auto mode shifts for you and manual lets you shift it via a nifty floor switch, which works slick.
I agree with most others, it should have a bit more overdrive gearing. I don't have a lockup converter so I don't see a full 700 RPM drop in overdrive. With my gearing 2750 RPM @ 71 MPH.
Aside from that, it was a very easy install, any good mechanic can do it.
Final thoughts;
Installation is a breeze.
Measure driveshaft "exact".
Key-hole crossmember holes would work fine, if did another- I might do that.
In the end: Nothing like cruising down the interstate 70+ waving at all the classic car fans.


