Steve Adkins

I am looking for some info on a Richmond 6 speed Trans. or any other type of
trans. that will lower my top end RPM's.

Stingy74

Try this:
http://www.richmondgear.com/cat/rod.html

Smokehouse69

Check out this link, info from a guy that has been there with pics. It isn't a Richmond Gears, but it is a T-56 6-speed.

http://forums.corvetteforum.com/zerothread?id=218566

CDaniel525

I know there a few guys on the forum with over drive manuals...there is the:
T56 - 6 speed
Tremec - 5 speed
Richmond Overdrive - 6 speed
Might be others though.

Chris

GWHITE75

Bob Turner has a Richmond Six speed in his car. Norvalwilhelm as a TKO 5 speed in his and I have a T-56 in mine.

BeaterShark

There is a guy (Twinnie) with a car in pieces who has "ZF-6" in his sig. I don't know if he has installed/driven it as it may be part of his current build-up.

MassVette

I have a R.O.D. in my '79. What do you need to know?
:chevy :chevy

GWHITE75

MassVette I forgot about you having the 6 speed. I wanted to tell you in another thread that your car looks great, as in show quality. From your sig, you have a 502, running 2-4's, along with the 6 speed. It looks like you're also running electric fans. What type? I assume they do the job for you, even during summer months, in higher temperatures with the A/C? I want to get rid of my mechanical fan and am looking into similar combinations. Have you changed the 502 from its stock set up inside?

Oh yeah, Go Patriots!! Big game this week.

SteveG75

MassVette,

Tell me about the 6 spd conversion. I was think 5 speed but time I added up new rear end gears (for the highway), tranny, shifter, etc, it was with $500 of the ROD.

Did you start with a 4spd or auto . Crossmember mods, etc.

My engine is out right now, and everything I have read implies that I can put the tranny in without any crossmember mods then add the engine.

Steve Adkins

Did you have to do any mod's to the crossmember? Does the driveline have to be altered? Does the shifter come up differently than the original? In your opinion would it be worth the change from my Munci 4-speed.

69 N.O.X. RATT

I just put the R.O.D. in my original 4 spd 69. The crossmember needs to be fabbed up for a 6 spd. We built a new crossmember and cut out the old one. The drive shaft needs shortened. You need to use the front yoke from a turbo 400. You may need to slightly cut away the opening for the shifter. It really a pretty simple swap. If you can afford it, the whole set up costs close to $3,500.00, it is more than worth it. I have the mathimatical equivalent of a 4.22 rear end ratio, and an over drive that turns 2180 rpms at 80 mph. The R.O.D is also a very strong street tranny.

The was an article on the idaho corvette page that went into a very detailed description on hoiw to do the swap. I would post the web page, but forget the exact address. :chevy

MassVette

On my 1979, I notched out the crossmember a little for the mount. I kept the stock driveshaft, using a TH400 front yoke. The shifter comes up in the same hole in the same place. If you have the $$$, it's the best change you could do. You gain torque from the extra gearing, plus you can take the car anywhere. There is nothing more humiliating than to have a high perf. 'vette being constantly passed on the highway by old ladies in Ford Focuses! This is the one thing that will solve the problem.

Here's a pic of the only major? mod I needed to do.



[Modified by MassVette, 7:14 AM 1/25/2002]

BeaterShark

How do you get this figure? My guess is that your are compariing the first gear from a Muncie to first gear in the ROD, with a rear gear ratio of 3.55. Am I close?

Here are my opinions on the popular overdrive trannys which are being swapped into the C3. Please don't get me wrong, I do wish that I had an overdrive on mine, but I can't afford it, so I have to come up with a reason why I don't want one :). I am not trying to discourage anybody from getting an OD tranny or saying that it is a bonehead move, I'm just giving my train of thought on why I could not justify one.

When I was doing my engine buildup, I had planned to get an overdrive tranny. Then, the stock market dropped and I could no longer afford one. The more I think about it, I don't think I could justfy it for me. One of the things that I noticed is that both the ROD and the Tremec both are wide ratio transmissions with killer 1'st gears but the second gear shift drops too much. Here is the percentage drops for the ROD, Tremec, and M20:
M20: 1-2: 74.6%, 2-3 78.2%, 3-4: 68%
Tremec: 1-2: 60.6%, 2-3: 67.7%, 3-4: 74.6%
ROD (3.27 1'st): 1-2: 65.1%, 2-3: 73.7%, 3-4: 78.3%
ROD (2.77 1'st): 1-2: 67.9%, 2-3: 77.7%, 3-4: 80.8%

So, as you can see, the deep fist gear comes at a cost to the rest of the gears, with the 2.77 1'st gear ROD being the exception (it's 1,2,3 are pretty close to the M20's). Based on this, none of these transmissions have an advantage to the Muncie in gears 1-4, so the advantage is in the overdrive.

Now, I ask myself why do I want an overdrive. The first thing that pops into my mind is to keep the revs down at highway speeds (70 - 80). Then I have to think about what is the advantage in keeping the revs down? One is for better gas mileage, but I'm not going to spend $2k - $3k to save about $200 a year in gas. The other is that an engine will live longer turning 2180 RPMs as opposed to turning 3500 RPMs (ROD vs M20 with 3.55 gears at 80 MPH). My opinion is the engine is performing at near the same RPMs for at least 80% of the time. I know there are probably some of you out there with more than 20% highway driving, but you are the exception, not the rule. So, instead of needing a rebuild at 150k miles, you will now need to rebuild the engine at about 10K -15K miles sooner. Again, I can't justify spending $2k - $3k to put off a rebuild a little longer.

Personally, I think that if I did have $2k - $3k, I'd go with a fuel injection setup first. Then if I had another $2 - $3k, I'd go with an OD tranny.

ScubaJKD

Interesting analysis.

:cheers:

Flareside

Very good analysis! I think that many people on the forum believe that an o/d gear is a necessity without understanding the whole equation.

By the way, did you know that you can spec. your ratios with the Richmond 5 speed? I'm running 3.04, 2.13, 1.57, 1.24, and 1.00 with 3:55 gears.

flynhi

Hi Chris, Another option would be a wide ratio 4 speed from TexRacing. I believe the Z or W ratio with a 3.08 will give a 10+ first gear ratio for great starts with a 1:1/3.08 final drive ratio. It's also a direct drop in at less than half the purchase cost of a ROD.
Contemporary engines have wide torque bands and IMHO don't need extra 2 gears.

Chuck Harmon

Unless you spend a lot of time on the highway, you can buy a lot of gas for the $1000 extra you spend for the ROD 6 instead of the ROD 5 speed. For me the money was worth not having to make a compromise. Yes, it is much more pleasant cruising at 80mph with a 2.53 overall gear ratio (3.08 x .82 = 2.53). But I also have a car capable of going well over 120 mph, better known as "Bragging Rights"!

Having a 1st gear equal to a 4.56 rear and M22 close ratio trans (4.56 x 2.20 = 10.03 is equal to Richmond 3.08axle x 3.27 first gear = 10.07) It is the best of all worlds!!

I show the spread between ROD gears to be:
1-2 = 54% 50 mph @ 6500RPM and 3.08 gears
2-3 = 36% 77 mph @ 6500RPM
3-4 = 28% 104 mph @ 6500RPM
4-5 = 23% 133 mph @ 6500RPM
5-6 = 22% 163 mph @ 6500RPM
Top End 200 mph @ 6500RPM

As you can see, only 1-2 is a big jump percentage wise, but only 27 mph in real life. I have more than enough torque to destroy the tires on this gear change. The rest of gears have virtually the same spread between them as the M22, approx 35%. A M22 3-4 shift is 21% which is about the same as my 5-6 shift.

The ROD 6 speed is a much more consistant and better spaced box than my ZO6 6 speed, it is all over the map regarding its ratios. The 2-3 change is much too steep and the 3-4 could be a little closer. The 5-6 change is absolutely ridiculous on a carburated car, but ok for 30 mpg w/ fuel injection.
1-2 43% 48 mph @ 6500RPM
2-3 59% 69 mph @ 6500RPM
3-4 30% 110 mph @ 6500RPM
4-5 19% 143 mph @ 6500RPM
5-6 50% 171 mph @ 6500RPM
Top Speed of 270 mph @ 6500RPM :rolleyes:

Chuck


[Modified by Chuck Harmon, 11:28 AM 1/25/2002]

MassVette

The ratios in my R.O.D. are VERY evenly spaced- and my .62 overdrive is fantastic. The car is both a BEAST at stoplights, and a guided missile on the interstate, if you wish it to be. I wouldn't give it up for ANYTHING. It completely transformed the car. If you drove it, you'd have to agree. I think it's money VERY well spent.

Bob Turner

I went with the six speed for these reasons:

1. Exotic swap into an older car (this case a '74 C3)
2. Six gears
3. Overdrive- .62 to one 1700 rpm's @ 70mph with 3.08 and 245/60/15's
4. Bulletproof design
5. Fun to drive!

I would say that I didn't worry about the cost of it since this is a project car and not a daily driver. If I was worried about recouping costs relating to gas mileage saved, I would sell BOTH Vettes and buy a new car. MassVette is right- I wouldn't give it up!!

If you want the cheapest overdrive trans swap, I would to with the Turbo 700 Automatic. You can buy and install one for around $1,700 or so.

I would go with any of the three six speeds (Richmond, T-56, and the ZF (even though I haven't seen this installed in a C3 yet). The Tremec 5 is also a good choice and probably the cheapest of the overdrive standard transmissions.

Bob :cheers:


[Modified by Bob Turner, 8:50 PM 1/25/2002]

69 N.O.X. RATT

Chris: You are very close I have a 3.36 rear end ratio with a 2.77 first gear. I took a lot of time in deciding to spend the money on the ROD. I live in southern california. At least 80% of my driving will be on the freeway, so the over drive is a huge benifit. The ROD is much stronger than a M20 or even M22. My car makes 575-600HP on the motor, before I get into a fogger system I have plumbed into the manifold. I do some drag racing with the car and wanted to make sure the tranny would live behind a nitroused big block. I priced some M22's that where built to take some drag racing and they were around $2200.00 For the benifit of the overdrive, not to mention the cool factor the ROD was well worth the extra $1200.00 or so.

If I lived in an area where I would not do so much long distance driving I would probably not have invested in the ROD :chevy