Long Term Transmission Plan...

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7milesout

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Guys,

I'm looking for advice. My 72 Scamp has been improved / repaired to the point over the past 1.25 years, since I took ownership, and has become a really great car. My goal has been to make it as close to a Toyota Camry as a 1972 Scamp can be, within reason. Don't get me wrong, I'm don't mean that I want it to be a 4 cylinder daily driver. I mean, I want it to be as good as it can be with what it currently has. An LA 360 with a 727, and 3.23 diff. As it is right now, it is quite good, and would run a 13.99 if I could leave the start line without spinning. I think it is about the equivalent of what a 1972 Camry would be, if there had been such a thing, and it had been built with a V8 engine. So I'm very happy with it. Everywhere I go I get one of two, or two of two reactions. 1) Either a thumbs up, or "I love your car," or 2) would you sell it? Continuous. The would you sell it does get a bit old.

The only thing I would like to get squared away with it is, the transmission. The 727 is great and all, but I would be on top of the world if I could just throw an O.D. gear on the end of it. You guys know my pain. I really don't like hearing it scream at speeds over 55 mph.

If I weren't concerned with keeping the car more original than not, I would prefer a manual transmission. But since I would prefer to keep it more original, I will keep an automatic. And I would prefer to keep it Mopar. I'm in no hurry to get this done. I have plenty of time to plan this out. Bear with me, as I don't know automatics. They are all magic on the inside to me.

I'm looking at stats on the 500 and the 518. The 500 seems like it would be a skosh quicker off the line and the same 1.00 (3rd), 0.69 (O.D.). But I wanna say that I've read the 518 is a better trans. Keeping with the robust / reliable / Camry type mentality, I will take reliable over quicker E.T.

The Gear Vendors offerings interest me, but know very little about it. Will keep reading there. Not original or Mopar I realize, but it seems to be very good quality. What I haven't figured out with GV is, is it a complete transmission replacement?

I'm all ears, and open to all suggestions to plan this out. Thanks in advance.


7milesout
 
"Hear it scream?" Just how small are your tires? Start by plugging your 3.23 and tire size into an online gear/ speed calculator. You just might do better with just bigger (taller) tires.

Example: My old RoadRunner had 3.54 Dana. It ran just about exactly 3K at 70 mph. Later I swapped a 340 into it. (Originally a 440-6). The 340 would get 17.5 mpg, not bad considering I was NEVER that careful with the throttle.
 
Original 14" wheels, with 215 / 60's on them. Very close to original tire sizes. I prefer to keep the original 14" wheels for as long as I can.

60 mph = 2,695 (basically 2,700) rpm
65 mph = 2,920 rpm
70 mph = 3,144 rpm


7milesout
 
I installed an A-500 in my Duster. I am very happy with it. It does require slight tunnel mods and a new trans mount cross member be built, but it was very worth it to me. I now find that my 3.23 gears can be swapped with something much lower and still be very highway friendly. Stock shifter will work since it's basically a 904 with an overdrive. All in all, an OD trans gives you flexibility you just don't have with a 3 speed.

Cley
 
7milesout said:
Guys,

I'm looking for advice. My 72 Scamp has been improved / repaired to the point over the past 1.25 years, since I took ownership, and has become a really great car. My goal has been to make it as close to a Toyota Camry as a 1972 Scamp can be, within reason. Don't get me wrong, I'm don't mean that I want it to be a 4 cylinder daily driver. I mean, I want it to be as good as it can be with what it currently has. An LA 360 with a 727, and 3.23 diff. As it is right now, it is quite good, and would run a 13.99 if I could leave the start line without spinning. I think it is about the equivalent of what a 1972 Camry would be, if there had been such a thing, and it had been built with a V8 engine. So I'm very happy with it. Everywhere I go I get one of two, or two of two reactions. 1) Either a thumbs up, or "I love your car," or 2) would you sell it? Continuous. The would you sell it does get a bit old.

The only thing I would like to get squared away with it is, the transmission. The 727 is great and all, but I would be on top of the world if I could just throw an O.D. gear on the end of it. You guys know my pain. I really don't like hearing it scream at speeds over 55 mph.

If I weren't concerned with keeping the car more original than not, I would prefer a manual transmission. But since I would prefer to keep it more original, I will keep an automatic. And I would prefer to keep it Mopar. I'm in no hurry to get this done. I have plenty of time to plan this out. Bear with me, as I don't know automatics. They are all magic on the inside to me.

I'm looking at stats on the 500 and the 518. The 500 seems like it would be a skosh quicker off the line and the same 1.00 (3rd), 0.69 (O.D.). But I wanna say that I've read the 518 is a better trans. Keeping with the robust / reliable / Camry type mentality, I will take reliable over quicker E.T.

The Gear Vendors offerings interest me, but know very little about it. Will keep reading there. Not original or Mopar I realize, but it seems to be very good quality. What I haven't figured out with GV is, is it a complete transmission replacement?

I'm all ears, and open to all suggestions to plan this out. Thanks in advance.


7milesout
Click to expand...

As already mentioned the GV overdrive goes on the back of your existing trans and also requires a driveline mod to shorten it down.
The A500 needs a shorter driveline, larger cooler lines, and a longer speedo cable, and a different cross member, but requires very little mods to the cars hump for clearance.
The 518 requires all the same mods as the A500 but also fairly extensive floor hump mods being that it physically larger.
You have to split and widen the hump for the 518.

Since I was able to do all the work it cost me about $150-200 just to get the A500 and install it in the car and another 150 for the Transgo stage 2 kit.
I probably have another 150 into a fully automatic shifting system for the OD and converter lock up.
So about 500 or so into it vs near 3k for the Gear Vendors.

The GV's are tough as hell and can handle tons of HP though, so no real concerns there.

"They" say there is an approximate 40% increase in fuel economy with the A500 over the 904 3 speed, but I took that with a grain of salt.
After all said and done I went from 17mpg hiway with a 318/904 to 25mpg hiway with the cammed 5.9 Magnum and the A500.
 
There are some funky transmission mods that have been done. As stated above, trans tunnel surgery is required in many of them, as well as drive shaft work. I know that some B-Body folks have opted for the GM 700R4 / 200-4R swap because there are very little body mods. There are adapter plates to bolt them to a Mopar engine. Still need to modify the trans support and drive shaft. I think it may be a less expensive route than GV, but I've never priced them. Good luck and have fun.
 
TrailBeast said:
As already mentioned the GV overdrive goes on the back of your existing trans and also requires a driveline mod to shorten it down.
The A500 needs a shorter driveline, larger cooler lines, and a longer speedo cable, and a different cross member, but requires very little mods to the cars hump for clearance.
The 518 requires all the same mods as the A500 but also fairly extensive floor hump mods being that it physically larger.
You have to split and widen the hump for the 518.

Since I was able to do all the work it cost me about $150-200 just to get the A500 and install it in the car and another 150 for the Transgo stage 2 kit.
I probably have another 150 into a fully automatic shifting system for the OD and converter lock up.
So about 500 or so into it vs near 3k for the Gear Vendors.

The GV's are tough as hell and can handle tons of HP though, so no real concerns there.

"They" say there is an approximate 40% increase in fuel economy with the A500 over the 904 3 speed, but I took that with a grain of salt.
After all said and done I went from 17mpg hiway with a 318/904 to 25mpg hiway with the cammed 5.9 Magnum and the A500.
Click to expand...

That is a really good summary. Appreciated.
 
Guys - Thanks for the feedback. I'm reading it all, and vetting it all. Whether what I think about what I read rules something out, or rules something in, that's exactly why I need your feedback. And it is much appreciated.

Here's where I'm leaning at the moment. Adding a dimple to the trans tunnels is not a big deal. More than a dimple, my seat cushion starts getting pulled up and in. On the other hand, I'm not looking forward to paying for a GV unit, but it does offer some advantages, as below:

  • I can continue with the A727, and simply add the GV unit to it. More inline with original. Sort of OEM+. Granted the car came with a 904 and a 318. Swapping to a 360 and a 727 was before my time.
  • Both the A727 and the GV unit are known to be robust. That keeps things more "Camry-ish."
  • In daily driver mode, I don't see the GV unit being any more useful than as an O.D. But hey, that's what this is all about. If there are more daily driver benefits, let me know.
  • In dragstrip mode, if one could get coordinated with the gear splitting, I would imagine the GV unit would lower E.T.
  • If I go down the Nitrous Plate path, that looks to be fun, the GV supports that real well.
One additional note on the drag strip / gear splitting. In keeping the car original, I am limited to skinny tires. The fenders are close on the outside and the leaf springs are close on the inside. I don't mind skinny tires, but they do present a problem at launch. Using the GV AutoLaunch I hope would help this situation. If I can control myself & smoothly apply the throttle on the line at launch, not easy to do, by the time my foot is to the floor it's trying to spin the tires due to rpm/power. I would hope that an AutoLaunch shift to first-over would bring the rpm down and limit the power to the point the tires wouldn't tend to spin. Yet the GV website says, "a shift under full throttle to 1st-over produces tire spinning torque." It might make things more difficult.

It would be a lot of fun to beat some pretty serious cars on the strip, in the ole Scamp on little skinny tires.
:lol:

7milesout
 
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