My Gear Vendors Install Thread - '67 Barracuda Notchback 340/416 Stroker

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MobileCustoms

MobileCustoms

You can twist perceptions, reality won't budge
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Hello!
I 'm just beginning the install of a Gear Vendors Overdrive in my '67 Barracuda and figured I'd start a thread with as many details as I can post along the way.

I started by reading through the install notes a couple of times so I could make a plan of attack and "hopefully" avoid too many mistakes along the way.
I plan to tackle all the electronic stuff first and then move on to the mechanical parts after that.
Cheers!
-Doug

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The new units come with a much smaller new controller module which is easier to find a place for. I placed mine inside the driver's side kick panel near the top of it. The first I did was to fab up a mounting bracket for the manual override switch and indicator lights. I'm planning to mount that on the bottom side of my dash just below the ignition key. I also moved the stock dimmer switch upward and inward a couple inches as suggested in their installation notes to allow the Gear Vendors footswitch to be mounted in the original dimmer switch location for ease of use.

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I then ran the 4 wires which are in 2 looms through a grommet in the firewall that go to the overdrive unit. 2 are for the speed sensor and 2 are for the activation switch on the overdrive body. I tucked them behind the steel brake lines and then made sure to keep them away from the hot exhaust tubes.
I ran a new power lead from the back side of the fuse block on a circuit that's switched with the key and is also not hot while cranking, as suggested. The ground wire will screw into the body behind the kick panel.
The rest of the remaining wires will be routed over the steering column and attached to the switch panel that I fabbed up. The switch needed a 13/16" hole with a small keyway filed in at the 3 0'clock position and the on-off indicator lights each required a 5/16" hole. They fit nice and snug.
I drilled the mounting holes so that a screwdriver would easily fit between the lights and switch when I go to mount it.

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I'll order a second dimmer switch grommet for the carpet and update as I go along.
 
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For modifying the tunnel area where the overdrive is said to make contact, my plan is to use a convex dimpling tool on my air hammer. I figure that should do a good job of slowly stretching the metal where needed rather than trying to beat it into submission with a big hammer. We shall see!
I also ordered a couple of angle finder tools to help with checking the driveline and pinion angles. I have a 340/727 combo and an 8 3/4" rearend.
I plan to install some 7/16 block plate spacers on the front spring mounts to push the rearend back a little bit, to help center the 295/55/15 tires in the rear wheel wells a little better. I'll do this before measuring for a new short drive shaft to be made.

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Last night, I finished up all of the electrical side of things and also started some disassembly for the mechanical side of things.
I mounted the switch panel that I had made and also made some labels for that panel as well as the floor switch... In case I die tomorrow and someone needs to know what they do. LOL
I also checked my driveline angles. Trans output shows 3 degrees down while pinion shows 3.5 degrees up. I ordered some 3 degree perch shims from Dr Diff. I think this should get me closer to in the sweet spot when it's under full load.
I also need to shorten my adjustable pinion snubber as it is making contact with the body in the lowest position. This is because I flipped the front leaf spring hangers to lower the rear end a little. The car has ESPO +1 inch leaf springs in it. Wish I would have gone with stock height.

If anyone has a stock pinion snubber for sale, or that I could try out to see how it sits/clears, let me know! I'd rather check a stock one before I cut down my adjustable one.
Cheers,
-Doug

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Not to de rail the install, but I thought with drive line angles, you wanted equal but opposite angles? Which it looks like you are darn close to?

3.5 down on trans
3 up on pinion
 
plumkrazee70 said:
Not to de rail the install, but I thought with drive line angles, you wanted equal but opposite angles? Which it looks like you are darn close to?

3.5 down on trans
3 up on pinion
Click to expand...
From everything that I've read, you want it to equal zero under full load, when the pinion comes up a few degrees. So the initial "resting angle" should be down 2-3 degrees so that it ends up near zero under full acceleration. That's what I'm shooting for by adding the pinion angle shims. And you have my numbers backwards. it's actually 3 down on the trans and 3.5 up on the pinion right now.
 
Kendog 170 said:
Do the floor button and dash button do the same thing? Looks good by the way.
Click to expand...
The dash button switches it from auto to manual mode. In manual mode, you use the floor switch to engage/disengage the overdrive. In auto mode, it is switched on/off based on the rpm signal from the speedo sensor. In either auto or manual, the control module switches the overdrive off below a certain mph and also prevents it from being engaged when you shift into reverse, which would cause bad damage. At least that's how the GV tech explained it to me.
 
64 AAR Valiant said:
I've done a few. Not to jink you, If you don't have to cut the tunnel and modify it I will be surprised.
Click to expand...
Me too. But I'm gonna give it my best shot and document everything I can here with plenty of good photos. I spent a ton of time making my car nice and want to keep the hacking to the bare minimum needed. -obviously
 
Well, good news so far! I got the new Gear Vendors tailshaft in and test fit with the crossmember loosely in place and everything looks not too bad at all. If it was centered just a little better it would almost fit with little to no tunnel mods. The first thing I made sure to do was to pop my distributor cap to make sure it doesn't hit the firewall when I lower the trans down to work on things.
I used the template pieces they included and hung them on a centering shaft which I also hung my digital angle finder on to make sure it was at the same angle as my output shaft. I did my best to take some decent photos, but without an extra set of hands it was hard to get the perfect angle on my phone camera while holding everything else in place.

I'll need to move my driveshaft loop rearward 8 or 9 inches and use the air hammer dimpling tool to make a few minor adjustments to the tunnel sides for a little more breathing room, according to my calculations so far. That may change once I actually bolt the overdrive up fully but I'm feeling pretty good at this point!
Right now, the tailshaft housing is actually sitting a tad higher than it will be because the floor jack has extra pressure on it so I could slide the crossmember up. The crossmember rear mount will draw the tailshaft down into it more when I tighten that center nut on the stud.

I probably won't be able to get much more done for a few days due to a busy schedule, and my band is playing Friday night so there's that...
Right now, at least, I'm pretty confident there will be NO cutting in my particular installation. Fingers crossed that it stays that way.
Cheers!
-Doug

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Awesome thread, I'll be following along. I'm about to do the install on my 4 speed 69 Swinger.

Keep up the great work!
 
I have a GV in my 72 duster. There was not cutting of the tunnel, there was one spot that was clearanced slightly. I don’t have the controller, and it survived a small oh **** going into reverse once. As for the snubber, if it’s the square tube one, you can cut it down on both sides to shorten it.

I’d take photos, but I have the GV box sitting in the garage and not in the car currently. I rebuild the 4 speed it’s set up on, been waiting for when I get some time to pull my motor out and freshen it up…
 
Well, my work schedule for today changed a little, so I made some more time to work on the Overdrive installation.
I transferred the paper template to a thin cardboard (beer case) and took some more careful measurements with the centering rod and angle finder in place.
I set it at a slightly higher angle than what my trans output is actually at which is 3 degrees down. I figured this would help make sure I gained adequate clearance.
I also made some minor adjustments to the rubber trans mount area to make sure the trans was centered better which shifted it over toward the passenger side by about 3/16". This made a nice difference. I always knew it was off a little. Old car tolerances weren't the best! I used a highlighter marker to show where I opened up the rubber trans mount holes just a little.
I used my heavy-duty air hammer with a dimpling tool to slowly work the driver's side of the tunnel out a little and it did a great job without beating up the lizard skin coating and paint, which made me very happy.
See the photos below as well as a boring 9 minute youtube video showing the air hammer work and the results. I tried my best to get good angles on the photos and video but because of shadows and lighting, it's not always easy to see exactly how much clearance is really there.

I ended up with about 1/4" to 3/8" of clearance all the way around which I will call good unless I find out otherwise when I bolt the overdrive up and raise it all back into place. I'm going to try to get to that this afternoon if time permits and post some more updates.
Thanks for looking! I hope this helps somebody who is considering pulling the trigger on one of these. I know every car and setup is different. I spent a good amount of time checking all my engine and trans mounts, etc. to make sure I started off on the best foot with the transmission point down the center of the tunnel as much as possible.
Next up is to remove the driveshaft loop so I can slide it rearward about 8 inches and then I'll lower the tailshaft back down and bolt up the overdrive portion & see how it fits.

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Here's that video of the air hammer work:
 
The overdrive is all bolted in and fits with adequate clearance. Best of all NO cutting and only minor dimpling to the tunnel in one area on the driver's side.
Just gotta do the final electrical connections on the overdrive unit and speed sensor. Next up is to shim the rearend back 7/16", Relocate the driveshaft loop, install the pinion angle shims and then measure for the driveshaft.
Feeling great!
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MobileCustoms said:
The overdrive is all bolted in and fits with adequate clearance. Best of all NO cutting and only minor dimpling to the tunnel in one area on the driver's side.
Just gotta do the final electrical connections on the overdrive unit and speed sensor. Next up is to shim the rearend back 7/16", Relocate the driveshaft loop, install the pinion angle shims and then measure for the driveshaft.
Feeling great!
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Click to expand...
Clean install, that looks great!
 
Desert rat has a good thread on this install on his (now mine) 67 notch. Drove it. 8 1/2 hours home, the gear vendors unit worked flawlessly
 
I've had my GV in a Duster 416 w 3.91 rear for over a year now. I'll share a few thoughts from a practical use. I'm using it completely different from how I envisioned.

- I bought a TA Cheetah switch for the shifter and installed the floor "dimmer" switch too. I wanted to try both ways. I "thought" I would be splitting gears and when you use the floor switch, that works much better for coordination. However, splitting gears in a 416 A Body is not needed. My 530HP/ 524TQ engine accelerates so rapidly it is a wasted and impractical effort. You can't even full throttle it without wheel spin. Best to keep both hands on the wheel and not do anything more that keeping it straight. On a lesser powered engine, this "might" be practical.

- So, while the floor mounted switch works well, I find it disrupts placing my left foot in a good resting spot. I'm considering going back to the shifter switch.

- I envisioned manually using the GV but find 95% of the time I just leave it in Auto Mode. I can still manually bang through 1, 2, and by 3rd or 45 MPH, I'm backing out anyway. It's nice just to have it come in automatically.

- When I'm driving 45 mph+, the drop on RPM makes a world of difference in noise and the car calms down. My convertor foot brake stalls at 2900 rpm and I had it made "tight". The drop in RPM at 60 mph is about 500 rpm. This fluctuates based on load, angle of car going up/ down a hill. The convertor sort of acts like a cvt since when you give it a little gas or go up a hill, it will rev up a little till it tightens up but when flat driving at constant throttle is when the GV really shows it's benefits.
 
Made some 1/2 aluminum blocks to shim my rearend back a little in order to center the larger tires (295/55/15 Drag Radials) in the wheel opening better. They were pretty tight to the front before. I replaced the stock spring hanger bolts with longer grade 8 bolts. I also flipped the spring hangers upside down to lower the rearend a bit. It was sitting pretty high with the ESPO +1 inch leaf springs. Then I measured for the new shorter driveshaft needed for the Overdrive.
I measured it at 31 1/2 inches from center to center of the u-joints. I'll drop the driveshaft off for shortening on Monday.
Getting close for a test drive! Hoping the driveshaft shop can get to it in short order.

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