Gear vender

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George L

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Mount Hope Ontario
Hopefully this is in the right area
Has any installed a gear vender overdrive unit
In their 73-76 duster

How much floor tunnel reconstruction needs to be done
 
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There's a member who put one in his son's Dart but I forget his name :BangHead: . I'm considering one for my 500in./727. They are strong and in my opinion easier than converting to a different OD tranny.
 
Easiest to chop out the rib from the top and weld strapping over it; just cover it with a slight carpet bulge. I've done a lot of cutting from underneath, and it gets old quick. And what for? to leave a couple of little strips that have to be welded to from underneath? The original factory reinforcement isn't attached to the tunnel very well at all, but welding from above makes for a nice solid floor above the trans crossmember. Now, If you have your car up-side-down on a rotisserie; that's a different story...lol..
 
Easiest to chop out the rib from the top and weld strapping over it; just cover it with a slight carpet bulge. I've done a lot of cutting from underneath, and it gets old quick. And what for? to leave a couple of little strips that have to be welded to from underneath? The original factory reinforcement isn't attached to the tunnel very well at all, but welding from above makes for a nice solid floor above the trans crossmember. Now, If you have your car up-side-down on a rotisserie; that's a different story...lol..


They car is actually being final paint next week,
 
It is NOT a bolt-in and drive deal.
But the fab work in my 68 Barracuda/same tunnel AFAIK, was minimal.
My tunnel only needed to be clearanced in two places, and the rear mount dropped a tad. But I needed a jack to push the GV up into the tunnel to identify the offending places, and then a BFG to pound in some clearance. The Unit will have to go up/come down several times. I did the work on a 4-post drive-on hoist.
After it was up as high as it would go, I determined it still needed ~.5 inch at the mount. What I did was simply slot out the holes in the crossmember, and let it droop. My driveshaft needed to be shortened and the pinion angle reset.
>The following is additional;
if you have a manual trans car. The front shifter pad on the adapter has to be partially cut off, this is not optional. Then you have to fabricate a new adapter to mount the shifter to the REAR mount.
>The following is optional;
I took this opportunity to move my shifter back about 8 inches and closer to my leg. Of course this required me to fabricate new longer/stronger/stiffer shiftrods.
 
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Im shocked these actually fit in that narrow tunnel! More expensive than a 200R4?
200R4 swap questions
 
I wish I could FIND a GV unit. My son is looking for one as well.both for 727s
I figured with all the old 440s being pulled out of motorhomes they'd be plentiful but no.
 
I wish I could FIND a GV unit. My son is looking for one as well.both for 727s
I figured with all the old 440s being pulled out of motorhomes they'd be plentiful but no.
IMO;
I think you might be better off with an A500/518 or one of the GM offerings.
The only reason I have a GVod is cuz I have a manual trans and I am
able to split gears with it.
If I was an automatic kind of guy, I would have one of the above.
Or, I would simply redesign my engine to run a regular loc-up Torqueflite.

Here are the clinchers;
If you break your GVod, it has to go back to the factory for a very expensive overhaul; cuz they will not sell you any tools.
Nor will they sell you a different adapter, without you sending them back the one you already own. The unit uses GM speed-O gears, so you may have to buy several, and/or a multiplier to run your Factory Speed-O-meter.
Whereas, you can get your A500 or 700R4 rebuilt anywhere, cuz any good trans shop will have all the tools required.
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What I mean is this; the 727 ratios are
2.45-1.45-1.00 with splits of .59/.69. For a performance streeter this is a real compromise. To be sporty, I like to gear my ride to run out of revs at the top of Second close to 60 mph. In this example; 4.56s will get you about 60*mph=5400, so that's right on.... except 65 in Drive =3690 at Zero-slip. And there-in lies the problem.
If you gear the car for 65=2700say, that requires 2700/3670 x 4.56=3.33s/ rounds to 3.23s. But 3.23s will hit 60 in Second at only 3900, and your SBM is barely awake at that rpm. So you might need a bigger engine with a smaller cam to make 3.23s work with Torqueflite.
Now if you study this out; you find that, what you really need is a specific overall Second gear ratio, that could be equal to about 6.80 This will get you 60= 5100(0% slip), say5600@10% slip, for a power peak around 5200 which is a nice friendly streetcam around 230*@.050 ..... or with Good heads maybe one size smaller.
OK, well 6.80 with a Torqueflite is; 6.80/1.45=4.69 gears; rounds down to 4.56s.
>But of all the autos that can easily be bolted to an SBM, the 700R4 has the highest Second gear at 1.63, so; 6.80/1.63=4.17 rear gear, rounds to 4.10s. Better than 4.56s for sure but still pretty far out there. And, it's about the best gearing you can get with an auto, for these parameters.
>whereas, the A500 has a pretty good Second gear at 1.54; so 6.80/1.54= 4.41 gears, rounds down to 4.30s, which will get you 60=5440 (10% slip) Not bad. Now, 5440 could be the shift rpm, and so the powerpeak could be at say 5000now, which points to a 224*cam@.050; or with good heads, maybe a size smaller.
>And 65=2400(zero-slip) Looking good.
The starter gear would be 4.30 x 2.74=11.78 which means for a streeter, you don't need much of a stall, if any.

Lets say you installed this A500 with 4.30s.
32mph would be 1710(0-Slip) in direct/2900 in Second at 10% slip/5170 in First@10% slip. Not the best in Second, so yur gonna need some torque, or a higher stall if you want performance. But Second road gear is 4.30 x 1.54=6.62 so maybe it will wind up fast enough for you. (my 367@6.82 Second roadgear, explodes the tires lol.)
>Ok now here is where the R700 sorta shines; Second roadgear is 4.56 x 1.63=7.41 and at 32 mph, the rpm would be 3250(10% slip). But 60=6100(10% slip) long past the powerpeak. and
65=2520(0-Slip) in overdrive.
For this reason I favor the A500. The 1-2 split is wider, but geared right, it just disappears in the starter gear.
*All calculations were done with 27" tires.
To recap, the ratios are;
2.45-1.45-1.00 for 727/904s
2.74-1.54-1.00-.69 for the A500
3.06-1.625-1.00-.70 for the 700R4
For 60=5600 in second, the Roadgears would need to be
with 1.45 second = 4.65 rounds to 4.56
with 1.54 second = 4.38 rounds to 4.30
with 1.625 second =4.15 rounds to 4.10
And so the road gears would be;
11.17-6.61-4.56 for the regular Torqueflites, and 65=3690
11.78-6.62-4.30-2.97 for the A500 ....................65=2400
12.55-6.66-4.10-2.87 for the 700R4 ................. 65=2320
11.17-6.61-4.56-3.56 for the 727/GVod ............ 65=2880

the 4L80 has tighter ratios of
2.48-1.48-1.00-.75 and splits that I really like, of
.597- .676-.75 but there is no way to get a decent overdrive, together with a nice 2nd.
Road gears would be;
11.31-6.75-4.56-3.42 and 65=2770 with 4.56s
10.66-6.36-4.30-3.225 and 65=2610 with 4.30s
But the splits are pretty nice.
I like 4.30s cuz it is the biggest gear to still have a 10T pinion, the ratio being 43/10=4.30
Whereas 4.56s are 41/9, 4.88s are 39/8 IIRC

sorry my post turned into a novel, again.
 
I don't think you have to worry about the repair cost of a GV, if they are handling the abuse of 2-3000 horsepower 6 second drag week cars getting launched at 5k+ rpm, I'm pretty sure your ~4-500 horse engine won't do a thing to it.
 
Thanks AJ, great info there. I don't have the knowledge but with an A500 are you talking small block? My RB 500 would be too much for it ? From years back I thought they can't take the abuse ? IDK just asking.
Sorry, not trying to Hyjack just looking for info. Thanks
 
I don't think you have to worry about the repair cost of a GV, if they are handling the abuse of 2-3000 horsepower 6 second drag week cars getting launched at 5k+ rpm, I'm pretty sure your ~4-500 horse engine won't do a thing to it.

Agreed. Mines been in service about 20 years. I used to use it to trap in the 1/8th mile. 2nd+OD was 6200RPM.
 
Agreed. Mines been in service about 20 years. I used to use it to trap in the 1/8th mile. 2nd+OD was 6200RPM.
same here; but with a Commando 4-speed and 3.55s, plus gear-splitting, I used 4 ratios in the Eighth trapping 93 in Second-over, at or near 6200. The road gears were 10.97-8.56-6.82-5.32 ....... splits of .78-.80-.78
In od, 65=2240
That's a hard combo to top.
 
But I have a /6 so a 500/518 won't bolt up.
And my kid has a 440 in a c body wagon, again a 518 won't bolt up that's why I'm thinking about gv.
 
Thanks AJ, great info there. I don't have the knowledge but with an A500 are you talking small block? My RB 500 would be too much for it ? From years back I thought they can't take the abuse ? IDK just asking.
Sorry, not trying to Hyjack just looking for info. Thanks

Oh yes, they can be adapted to mount to a BB. And built to handle pretty good power.
If you need more, the A518 is based off the 727 guts with the same overdrive unit. The BB will be fine with the standard ratios of 2.45-1.45-1.00-.69od.

If I had an A500, (2.74-1.54-1.00-.69od), and was 30 years younger, and not expecting Armageddon in the next few years;
I would try to figure out how to use that .69od unit as a splitter. The ratios would be;
2.74-1.89-1.54- 1.06/1.00-.69. with splits of .69- .81-.69-skip direct and straight to 3rd/od =.65; this being a 6-speed auto, driven as a 5-speed; because of the 1.06/1.00, 4/5 gear situation.
I'd install that behind a 318 or possibly a 340, and run a 318-type cam, Daymn that would haul.
I would gear it for 65= about 1850, so maybe 3.23s out back. The roadgears would be
8.85-6.11-4.97-3.42-2.28, for 65=1845 in loc-up. I would run just enough stall to waste the tires at WOT, all thru first gear, and with a spreadbore, and Ima gonna try an old Dual-Port intake that I bought of a fellow FABO member, and that still sits on the shelf, waiting for a home..
The convertor at Zero mph, might have a ratio of 1.8, and at WOT, this would diminish progressively as roadspeed increased, and increase progressively as torque increased. Then the loc-up would kill the slip for cruising. The road gears might look like;
15.93 to 10.62-7.03-5.47-3.70-2.46/2.28 that will act like 6 gears plus loc-up

Of course as a streeter, at WOT, I gotta shut down at around 65 so , I'd probably only use up to 5.47 ratio, in the which; 5000=72 mph. In other words; Second-over will only rarely be used.
5.47 is a pretty good gear for trapping in the Eighth. But
there is no good ratio here for the Quarter.
Actually, if I was also rich, I would use a 273 and turbo it.
So many ideas, so little time.
 
But I have a /6 so a 500/518 won't bolt up.
And my kid has a 440 in a c body wagon, again a 518 won't bolt up that's why I'm thinking about gv.
There is/are companys that can provide an adapter bellhouse. Maybe they do slanty bells too, IDK.
JW Performance Ultra-Bell" is one.
Below is a bell for BB to 727. I also saw one for BB to TH350; so that should include the 700R4/ 4L60 series.
They appear to bolt on to the pump; so you can use your trans with the bell cut/machined off.
BTW
You probably know that the GVod can be had as a stand alone unit. You would have to build a mount for it, which probably means cutting up the floor a bit, but that would make it transferable, without adapters.
jpt-92460_ml.jpg

But, I was thinking, with a 440, on the street, is there really a need for an overdrive. I'm talking street duty.
I didn't buy my GV for it's reduced cruise rpm; I have never even installed the little controller it comes with.
No; I bought it to split gears with, so I could run a small-cammed, small engine, and have BB type Eighth-mile performance, yet the small cam would get me plenty of bottom-end BB-type torque, yet 318 type fuel economy.
If I actually had a BB, and needed the reduced hiway rpm, I would just gear the back for whatever rpm I wanted, and then to get the First-gear performance back, I would just increase the stall.
By the time you get a new GV installed, what are you looking at? $4000? or more?
What's a good used 3.23 chunk worth? (I mean people almost give these away, and I bet you already have one), and a new 2800/3000stall TC? I mean both together will be a fraction of the installed cost of a new GVod.
Even an Ultra-Bell plus a usable A518, no hi-stall, and no rear gear change; will probably come in at a similar price to the hi-way gear/ hi-stall combo.

Maybe there is even a company that makes a flat-plate adapter to bolt an A518 directly to the BB; IDK. Many many years ago I think there was.

Ima thinking you have already explored all these ideas so Ima probably just blowing smoke ....................
 
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Guessing the driveshaft isn't insanely short on a 108" WB car? Always worried that would be an issue.
 
If I had an A500, (2.74-1.54-1.00-.69od)...
I would try to figure out how to use that .69od unit as a splitter.

As in engage OD between the regular gears?? Could that actually be done with an A500?
 
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