I am in need of a transmission for my 1967 632" Corvette. I am hoping I can get some good recommendations for a trans that will fit the bill. The car makes over 900 rwhp naturally aspirated and 1375 rwhp on nitrous.

That being said, I have to say that I will probably never drag race the car. I have a DynoJet at my house and I use it quite often for all kinds of testing and fun.

I will give you a brief summary of my transmission experience so far with this car so you will know where I am coming from.

I originally had a G-Force GF-5R in the car. I was quite thrilled with it but after a while I got tired of having to slam gears. Downshifts especially sounded like the trans was going to drop out of the car! Before I purchased the trans, I had thought I would drag race the car but due to some pesky NHRA safety issues (such as roll cage) I decided not to.

I convinced myself that a PG would be the way to go so I ordered a full-kill Top Dawg unit from Coan with a bolt-together converter and the works. I told Art at Coan that I was a dyno racer and could not tolerate much loss in rwhp or rwtq and he said their Top Dawg was the way to go. Well, I lost over 100 rwhp after installing the PG. I immediately pulled it out. I wanted to make sure something hadn't happened to the motor so I needed to make some runs with a manual transmission. Unfortunately, in the meantime I had sold the GF-5R trans to Mark(ML67) so I installed a Tremec TKO-600 that my son was going to be putting in his C3.

I made a few runs with the Tremec and sure enough the power went right back up to 900+ rwhp. I was sick about the PG and it now sits in a corner of my shop. At any rate, I wanted to make a few nitrous runs and decided to leave the TKO-600 in the car. If it blew, I would just replace it. Well, it didn't blow. I made 4 nitrous runs with the best being 1374.77 rwhp and 1233.20 rwtq.

My son was wanting the TKO back to finish his car so out it came. I removed the nitrous and wanted to test out a tunnel ram that I had so I decided to install a Richmond 6 speed overdrive trans that I had laying around.

Keeping in mind that the Richmond 6 speed is only rated for something like 400 lbs/ft of torque, I fully expected problems. On the first run, I braced myself and prepared for the worst. To my surprise, the run went flawlessly. The car made 980 rwhp and 825 rwtq. I made a total of 13 runs with the tunnel ram and then went back to the single 4 and made 17 more runs - all with zero transmission problems.

I am quite frankly suprised at how much rwhp and rwtq all of these transmissions were able to support. I had always heard that a DynoJet was real hard on transmissions but this kind of dispells that myth. I think that starting line launch's and driveline shocks are what kills these things.

In case you are wondering why I don't want to buy another TKO or keep the Richmond 6 speed in the car, it is because I don't like the way they shift under any kind of load.

I like the simplicity of a 4 speed and since I am not in need of an overdrive, I think that will be the best for this car. I don't want to go with either a Jerico or G-Force 4-speed due to having the same shifting issues that I disliked about the GF-5R.

So, what do you think? Any recommendation's?

I have heard that the new Autogear M-22 is a pretty stout unit and hopefully someone has some experience.


Steve

 

The auto gear is probably a good choice. The super case, large outputshaft and cast iron midplate should hold fine if the others did. The muncie problem of pulling itself apart is fixed with the midplate and the supercase. You can get it in a wide ratio for the street as well if desired.

 

Hey Steve,

I'm not familiar with the Autogear M-22, so I can't comment on that. But I'd have to say that maybe you should reconsider the G-Force 4-speed. Its the one I've decided to run myself, and hey, its got one less gear to have to shift than the earlier G-Force GF-5R. I know Mark loves it, even with all the shifting. Anyway, if you just blip the throttle, when the clutch is in during downshifts, it shouldn't sound like the trans is going to drop out of the car. Heck, that non-syncro style trans is a real man's trans. To me, your engine calls for a trans just such as that. Good luck with whatever you decide to go with.

 

http://www.libertysgears.com/index.html
these guys may help.

seems like most companys still use the original doug nash style layout.

AGE makes pretty much anything for muncie based trans and new cases

jerichos remind me of old ford toploadersI know several guys who broke these.

why dont you put in a 4L80 and paddleshifters

 

I sold my Autogear M-22 but the guy that built it for me ran one exactly like it in his 57 Chevy. Full rollcage, Full interior, street legal. He had a 540 with three stages of nitrous. 1100 HP and ran it for three years every weekend at the dragstrip with slicks with no issues. Will PM contact information.

 

http://cgi.ebay.com/ebaymotors/NOS-D...1%7C240%3A1318

 

I will definitely do some more research on this trans. Thanks!

I understand where you are coming from because I used to feel the same way. Heck, I'm the one who convinced Jim Moore to put one in his car. I purchased the trans in August of 2002 and sold it to Mark in early 2007. That is quite enough time for that type of trans for me. It was not only the slamming gears but possibly more annoying was the constant banging inside the trans while trying to maintain any type of cruising situation. Due to the characteristics of the cams I run and the excessive gear "slop", this loping condition was driving me crazy towards the end. Hey, this even occurred when I had the 542" motor in the car with a 261*/269* @ .050" cam. So unless you are planning on drag racing the car like Jim, you might want to reconsider. If you are planning on drag racing the car, the G-Force's are impossible to beat.

I will check into what Liberty has to offer. As far as the 4L80, I would probably lose 200 rwhp with that thing!

Now we are talking!! I look forward to receiving your PM. Thanks!

V77Vette: Thanks, but I definitely want to stick with a 4 speed.

Steve

 

Can't help you out on the trans but I would love to be your neighbor. Every time I would here that car fire up you would have company. Love to hear your dyno runs!
No personal experience but I have heard great things about the Auto gear M 22.

 

Thanks, Gordon. It is too bad that you are on the other side of the country! If you were to ever get out this way, well you know.

Steve

 

Sent PM. Dave builds his a little different than most to handle more power. One difference is he uses a grooved bronze sleeve instead of a rollerized 1st gear and all components are Autogear except the Italian gear sets. Be very careful as all Autogear transmissions are not built to the same standards. Some E-bay vendors substitute some internal components and inferior quality gear sets to save money. The M-22 gear set is much stronger than the wide ratio set.

 

There is a wide ratio set cut on the angles and strengths of the GM M-22 set.
http://www.dandltransmission.com/

part number: M22WGS
Complete M-22 gear set wide ratio 2.56 1st, 1.75 2nd, 1.36 3rd
$650.00

verses this:
M-20GS
Complete wide ratio M-20 gear set (1" only)
525.00

Then here are the trannies:
18.000-001
Complete new M-22 close ratio transmission Autogear supercase, super tail,
super side cover, all new ports, steel bearing support,
10 spline in- 27 spline out,
26 spline in -32 out
--your choice
1,800.00

18.000-002
Complete new M-22 wide ratio same specs as above
1,865.00

 

Same gear manufacturer Dave uses.Daves transmissions are a little bit higher priced.

 

Scott -- Are you currently running the M22w that you have given these specs on? If so, what is your opinion as far as high rpm shifting?

Kevin -- You said you had an Autogear M-22. Were you able to run it before you sold it? If so, how about your opinion?

Steve

 

No, sold it uninstalled. Went with a D&D Chevy-Viper 6 speed. I built the M-22 for my 63. When I went to Tom's for the differential I could only get a 4.11 or 4.56. With those choices I needed an OD for my application so I changed plans. The ratios on the D&D unit work well with my 4.11 rear gear. If I had a 3.73 rear gear I would have kept the Autogear M-22.

 

Not to get off the subject here, but how did you fit the T56 in your car? From what I have heard, the shifter location is a serious problem.

Steve

 

I bought the gears and most other parts and built it myself. It shifts great to about 7000rpm. I have shifted above this but not sure of the exact number. A good clutch is more important for shifts. B&B style instead of diaphragm... The centrifugal weights help on a CF dual friction but it is just not the same.
-Scott

 

Scott, I appreciate your feedback and help. I have a McLeod Street Twin in the car and just love it.

Are you powershifting the car at 7000 rpm or speedshifting? I have a Tremec TKO-600 in my '67 383" convertible that went 11.93@114.99 but was too afraid of trying to powershift it. Heck at 6500 rpm that trans would grind when going from 2nd to 3rd.

BTW, I see that you have a Tri-Power on your car. I am restoring a '69 T-Top and am going to be putting together a 496 with factory Tri-Power and cast iron exhaust manifolds. I want to use the factory 427 hood. Are you happy with your Tri-Power? Also, do you plan on racing the car again? 11.30 @ 124 is flat awesome. I am totally impressed that you are doing it with 2-1/2" exhaust! I mean, with that cam I can't imagine how much you are giving up with 2-1/2" exhaust.

Steve

 

Actually on that run, I dropped a valve about 100' before the line and coasted through. I was short shifting (~6000rpm) and granny shifting it on that run. Also I launched at only 3000rpm with 32psi in the tires (supposed to be a warm-up run). I had a proshifted m22 that I powershifted in another car.
I used my tripower for a daily driver for about a month. I won't powershift syncros, they will not last long. It is all in the engine combination not just parts.
I am now moving to a 498 since the dropped valve broke lots of parts... bore needs to go to .070" now. I love the tripower.

 

Amen to the syncros not living very long when being subjected to powershifts. (BTDT)

While I can't afford the complete AutoGear super-Muncie, the M22 wide ratio gearset is front and center on my current overhaul wish list, along with the mid-plate and other bits. I don't have any future plans to drag race my C3, so I believe it ought to handle the mere ~500hp it'll see out of my next build up. See there's yet another vote for the McLeod street twin. Looks as if that may deserve a spot on my wish list, too.

Back on point, IMHO when behind an engine with a broad power band, the wide ratio steps make good sense vs. those of the close ratio, which is all about keeping revs within a narrower band.


BTW, I'm curious to know who proshifted your M22 and, in particular, how well it downshifted.

 

Steve, Steve, Steve........the problem is you were just driving it too slow!

Having driven crash box Muncies and T-10's for years on the street.....I am just flat in love with the GF5R you convinced me to buy. It's by far one of the best/fun things I've done with the car! Pulling that Long shifter at 7500 rpm or so is just pure magic!

I think you're pretty much limited to a synchro trans if you don't want the *slop* that a dog ring/face plated setup has. That's why they shift so well It's because there is a great big window for the slider to fit into when you shift. Of course if you *goose it* or let on and off rapidly you'll feel that slop. A big 'ole cam thumping can make it happen too if you end up in the *sweet spot* and keep it there.

But I have to say, I just don't notice it much on mine. Mark has ridden in and driven it too...that's what convinced him to buy yours! It does take a little practice to drive..and it won't ever be as smooth at low speeds as a synchro...but it can be reasonably smooth.

For the 632......I would still like to see something with some strength. Obviously the TKO and Richmond did OK on the dyno....but I wouldn't give either one of them any hope with some traction and a 7000 rpm shift in your car. The dyno is a pretty smooth deal as compared to banging it down the track.

The T-56 is going to be about the strongest thing I can think of with a synchro. G-Force makes them too. Not sure of fitment..but I know of a couple of C-3's that have managed to put them in without too much drama. I wonder if Liberty makes a synchro straight cut gear setup for a Muncie? I bet they could if you asked.

Then there is the Lenco ST1200..but they say they eat some power too. But being a planetary trans shouldn't be any slop in it...and smooth to drive. They freewheel when you let off..so no jerking.

Let's get that thing running..one of these days when I'm up there I want to go riding...at about midnight when no one is around!!


JIM