Gear Vendors OD

[SK8BALL]

Looking at putting on a Gear Vendors unit on the car.
I do ALOT of long road trips 200-300 miles.
RPM at highway speed is too high.
Looking to reduce RPM & increase MPG.
Looks like a great bolt on solution.

74 Charger
318
904 Tranny
3.21 Rear End
27” Tires

Anyone done this in a 74 Charger?
Any trouble with the fit in the tunnel?
Any other information would be great.

 

[snakeoil24]

That’s a big car and adding gear vendor unit likely won’t do much

 

[Mike Brini]

Have given this some thought as well. Personally I think the best bang for buck is swapping tranny to an A518. It has overdrive and the only mods needed are the trans mount and shorten the drive shaft. IMHO

 

[dan juhasz]

I ordered one for my 67. In overdrive my 3:91 gear will become a 3:04 ratio. Only downside is a 12 week wait to receive.

 

[topside]

In the '90s I put a GV in my Dually. MPG went up 20% (4.10 gear), RPM is perfectly in the torque curve @ 65-70 MPH, and it's been bulletproof.
I'm unsure if floor mods are needed for the 518, or what the converter requires - lockup ? - but both need some looking into. Plus shifter mods, right ?
OD vs GV kinda seems to be a wash on BB cars cost-wise at least.

 

[33 IMP]

I would put a GV on a big block car with gear. They are very strong, and there simply isnt a good factory overdrive for the big block bolt pattern, other than a bellhousing swap to a small blockor GM trans.
For a small block car with no gear to speak of, I'd stick with a Mopar 500 or 518. Floor mods should be done. I'm sure there are threads about it here, or on A-bodies.
Have you calculated your final drive ratio with the OD? In OD with 3.23 in the rear....... I'll bet you would be lugging the engine horribly below 80-85mph.

 

[Sixpactogo]

Not to rain on your parade but I put a gear vendor in my 440 powered 78 D150 many years ago when I thought it would improve my mileage by lowering the RPM's.
The gear vendor will give you a 22% final drive so it would end up giving you a 2.50 final gear in place the 3.21
That is the same ratio I ended up with in my truck. It brought the rpms down but it also brought the vacuum down enough that my mileage stayed the same. About 11 mpg. For me it was a waste of $3000.00. I ended up selling the whole works. I had 31" tall tires and yours are shorter so it will help your RPM's but who knows how long it will take to save $3000.00 worth of fuel. For my money, I would swap in a 2.76 rear or a 518 trans and save a ton of money.

 

[Kern Dog]

That’s a big car and adding gear vendor unit likely won’t do much

FALSE.
I had a GV in my '70 Charger, a heavier car. The 22% rpm reduction helps. The .78 ratio isn't the best but it is something.
The 3.21 axle ratio will act like a 2.50 gear.
The advantages are numerous. ALL new cars use some manner of overdrive in top gear.
Lower engine rpms at cruising speeds means a quieter interior, less wear on the engine and transmission, usually better mileage too.(Unless the engine has a wild camshaft that is terribly inefficient at low rpms)
One way to go may be the A-500 transmission. These were overdrive versions of the 904 and with that comes additional advantages.
The A-500 has a lower first gear at 2.74 vs 2.45. This will give more leverage from a stop and get a heavier car moving quicker. The OD is a .69, much better than the Gear Vendors. The lock-up converter reduces cruising rpms even more.
The Gear Vendors may end up costing more but it can take a lot more abuse.

 

[66/440]

PATC Dodge Performance Transmissions, 46RE, 47RE, 48RE, 68RFE

PATC Dodge Performance Transmissions, 46RE, 47RE, 48RE, 68RFE, 518, 46RH, 727, 45RFE and others. PATC builds Dodge performance transmissions in many levels.

transmissioncenter.net

 

[JimKueneman]

FALSE.
I had a GV in my '70 Charger, a heavier car. The 22% rpm reduction helps. The .78 ratio isn't the best but it is something.
The 3.21 axle ratio will act like a 2.50 gear.
The advantages are numerous. ALL new cars use some manner of overdrive in top gear.
Lower engine rpms at cruising speeds means a quieter interior, less wear on the engine and transmission, usually better mileage too.(Unless the engine has a wild camshaft that is terribly inefficient at low rpms)
One way to go may be the A-500 transmission. These were overdrive versions of the 904 and with that comes additional advantages.
The A-500 has a lower first gear at 2.74 vs 2.45. This will give more leverage from a stop and get a heavier car moving quicker. The OD is a .69, much better than the Gear Vendors. The lock-up converter reduces cruising rpms even more.
The Gear Vendors may end up costing more but it can take a lot more abuse.

The basic inputs to fuel usage and are mostly equally weighted

- RPM (22% reduction should yield similar increase in fuel economy)
- Engine displacement
- Engine Volumetric efficiency (typically 75%/85% and hard to get into the 90's so this the the smallest bang for the buck as a 10% increase here is a lot of work)
- Friction (aerodynamics)

 

[HawkRod]

I have a GV in my 73 Road Runner - essentially the same car from a structure perspective. I used it when I drove the car over 11,000 miles across country. (Look up RoadKill Runner if you want to check it out)

Did it help? You bet, in lots of ways. Of course, it lowers RPM, and that reduces engine speed. As long as your engine has the torque to drive the car at that RPM, you will reduce fuel costs. It also makes the car nicer to drive in since the engine is not revving as hard.

To install it, they say you just have to put "a couple of small dents" in the transmission tunnel. That was not my experience - I had to beat the tunnel pretty hard to get it to fit. But once it was in it has performed flawlessly and I am happy with it.

Is it worth $3000? Only you can answer that. The pure payback in dollars will probably take longer than it is worth, but then you have to ask yourself what the price is for additional comfort while driving.

Good luck.

 

[fesser]

There is also the ability to "split" gears that you won't get with an adapted 4 speed overdrive. Might not mean all that much, but I can't help but notice that almost all modern performance vehicles are running automatics with a lot more than four gears. If someone worked out the numbers, it seems that you could gear the car, to work with the engine's sweet spot, and gain a lot as far as driveability and performance. That's what I am hoping to accomplish with a GV, but I am long way away from driving my car.

 

[WS23U1]

Does anyone know how much these weigh? Ans how much are they today? Thanks.

 

[SK8BALL]

OK. The crowd seems somewhat split.
I don’t have the equipment or desire to do a full
tranny rebuild and swap and I don’t weld.
So if I have to pay a shop to do it it will be $$$$$$$.
After doing some calculations on the a500 swap,
it looks like somewhere between $4000–$5000.
At that price the $3000 GV unit looks like a bargain.
And I can do it myself!

 

[Kern Dog]

Holy crap, THAT is the quote you got for a trans rebuild ??
I can find a used A-500 locally within a week and have a rebuilder go through it for under $1000.

 

[SK8BALL]

Most of the tranny shops I talked to did not
want to have any part of it. The ones that seemed
to know their stuff were expensive.

 

[Kern Dog]

Most of the tranny shops I talked to did not
want to have any part of it. The ones that seemed
to know their stuff were expensive.

Any part of what? Rebuilding a core that you brought in? Is this an installed price?
Car enthusiasts that pay others to build their cars will always spend way too much.
You wrote:


"I don’t have the equipment or desire to do a full
tranny rebuild and swap and I don’t weld.
So if I have to pay a shop to do it it will be $$$$$$$."

I don't rebuild transmissions either but I've had good luck with used ones. A 318 car isn't very hard on transmissions so a clean used one may last you a long time.
Nobody here was born with the skills to be a master mechanic. I'm still not but what I am is adventurous enough to try things. I can weld but I'm not good enough to charge anyone for my work. My stuff holds together. The things that many of us know are also within YOUR reach if you try.
The Gear Vendors is an easy way to obtain an overdrive gear. It can be installed by a person with moderate skills. It isn't the best option in my opinion but you're free to make your own decisions.

 

[snakeoil24]

FALSE.
I had a GV in my '70 Charger, a heavier car. The 22% rpm reduction helps. The .78 ratio isn't the best but it is something.
The 3.21 axle ratio will act like a 2.50 gear.
The advantages are numerous. ALL new cars use some manner of overdrive in top gear.
Lower engine rpms at cruising speeds means a quieter interior, less wear on the engine and transmission, usually better mileage too.(Unless the engine has a wild camshaft that is terribly inefficient at low rpms)
One way to go may be the A-500 transmission. These were overdrive versions of the 904 and with that comes additional advantages.
The A-500 has a lower first gear at 2.74 vs 2.45. This will give more leverage from a stop and get a heavier car moving quicker. The OD is a .69, much better than the Gear Vendors. The lock-up converter reduces cruising rpms even more.
The Gear Vendors may end up costing more but it can take a lot more abuse.

The return on investment isn’t their kern already has a good rear gear and small engine. The 518 will give a better return

 

[Pool Fixer]

Before you do anything, use this easy calculator.

speed/rpm calculator

According to that, you currently run 62.2mph @2500 rpm
add the GV and you'd be runniung 82.9 mph @2500 rpm

If you were running a steep gear in an easy to swap 8 3/4 behind a big block with tons of torque, I'd suggest moving to a taller gear set. But you run a s/b and a pretty tall gear to begin with, I vote Gear Vendors for the win.

 

[Kultin]

I would guess the gear vendor unit weighs about 70lbs. Not to include the housing extension. The instructions are conflicting, either you slot the transmission crossmember bolts .1"down or beat the floor in. I used an air chisel with a rounded head to beat the floor in. I had maybe 1/8 clearance after doing so, but that is all they require. I used a poly tran mount which was just a tad taller than a regular rubber one. Small block 408/ 727. 3.73gear, 27"tire. 1966 belvedere 2