80saintnick

Has anyone converted a 4speed to a 6-speed? If so was the 6 a stock vette (ZF) or a richmond? How much trouble am I getting myself in for? I really like my 80 and the 6 would be something most have never seen. Thanks for all your help.

LT-1 Larry

I am in the process of dropping a Richmond 5-speed into my '71. It takes a bit of re-engineering the rear mount and it is definately heavier than the Muncie, but it is do-able. One thing I did that I would highly recommend is getting a removable center cross-member from a C-3 automatic and replacing your welded-in member with it. I did that and it makes it a lot easier to get the tranny in and out. I would especially recommend this if you are going to a Richmond 6-speed, because they require even a bit more of a radical change to the rear mount, and they say you have to take the tail shaft housing off to get it in. There's a TON of good info in the archives on this subject. Just search on 6-speed or Richmond - and good luck.

spikezz4

I went to a Richmond 5-spd and changed the rear end to 3.08 back in 1992. It changed the car for the better, almost as if "gee, why didn't St. Louis do this?". For the rebuild, we are going to the 6-spd with the same ratios in the gearbox, but OD for extra fuel mileage. The rear gears change to 3.07 with the Dana 44 rear end.

Once you have driven a 5 or 6 speed modified car even for a short time, you will not want to return to what you had. I can almost guarantee it!

Spike

hubes

This should help http://temp.corvetteforum.net/c3/gwhite75/index.htm :cheers:

MassVette

R.O.D. six speed is the same length as a T-10 or Muncie........the good news is- it's almost a bolt-in, UNLIKE all the other overdrives. Even the shifter comes up in the same place. The bad news is (on a manual trans C-3)- unless you pull the motor (or modify the crossmember for removeability), it ain't goin' in. The auto trans. C-3 has a removeable crossmember- which is what I used for the '79 conversion. I also converted the '67 (which is the same frame as the M/T C-3), but did it when I put in a new engine.
Oh yeah......the other bad news is the price- $2800.
:yesnod: :chevy :chevy :yesnod:

Ryan77

I was originally going to go with a TKO 5 speed because I thought the 6 speeds were to much of a pain in the butt. But, if the R.O.D. would go in pretty easily if I changed to an auto tranny crossmember, then I'll go with R.O.D. 6 speed. Where do you get them from? Any other mods neccessary to make it work? Thanks in advance :cheers:

Steve Straus

I think you have to change your frame to do that. If not, I want to know too.

MassVette

You can either cut the c-member with a sawzall almost to the frame rails, leaving 'ears' to bolt the auto. Auto. crossmembers are available from a number of Corvette suppliers. - or you can cut the center section of your c-member, weld ears to it and bolt it back on.
not that big a deal..........
:yesnod:

70 LS1

I am using a Borg Warner (Tremec) T56 and it is anything but bolt in. Go for the ROD 6.

80saintnick

Hey guy thanks alot for the help. I will stay away from the T56. Has anyone tried the ZF six speeds found in the "89-96 Corvettes?
Also, I have researched a number of suppliers for the R.O.D. and the cheapest one so far is Jegs 2829.99-3039.99 (depending on gr ratios) plus shipping (which is 85.00 through summit). Unless anyone has found one any cheaper?
Thanks again for all your help,
Don


[Modified by 80saintnick, 1:05 AM 1/20/2003]

70 LS1

The ZF is very similar to the T56 and has a lot of the same issues.

Twin_Turbo

Yup! I have one. I'm running a 84-86 4+3 single mass flywheel (because the pressure plate bolts to that and not ot the C3 flywheel), LT-5 pressure plate (thicker than the LT-1/LT-4 one). The installation isn't that bad, the mounting pad for the torque arm 9original on C4) is directly above the trans crossmember. All I need is to fab a bracket (but it's so darn cold so it'll have to wait).

The wood is there just for lifting the tranny so the driveshaft isn't angled.






For the rest it's requires a little cutting on the transmission tunnel, a little messing around with the hydraulic clutch and that's just about it... oh yeah, you need an electric speedo. I think it's a good excuse to get a 200MPH Electronic UltraLite ;)

Marck

jamesx0

Do you have to hack up the frame of a 4-speed car, or do you just have to deal with pulling the engine to pull the tranny? What about tunnel clearance?

MassVette

Either pull the engine, or cut the c-member. Tunnel clearance is OK- might have to "dimple" for the reverse rod, though.
:yesnod: :chevy :chevy :yesnod:
And Jeg's is the cheapest I've seen for the R.O.D., BTW............

Eddie 70

This is one more of the things I will have to put on my wish list.

Bob Turner

Twin Turbo,

Nice shots of that ZF. You are the first one that I know of that is going to run a ZF in a C3. Nice!

Bob :cool:

80saintnick

MassVette,
Nice Vettes! What rear gear ratios are you running? Also, what transmission ratios of the R.O.D. (a few different ones are available) are you running in each of these great cars?
Thank you for your help,
Don


[Modified by 80saintnick, 7:00 PM 1/21/2003]

69schemers

Twin Turbo, have you placed your body back on your frame to see the shifter to output shaft location? I am doing a body off restoration of 69 and mocked up a ZF in my car but did not care for the way the shifter ended up so close to the drivers seat and steering wheel. Do you plain on modifing the crossmember to make it removable and help get the exhaust away from the transmission? I ended up selling my ZF and bought a T-56.

80saintnick

Twin Turbo,
Great pictures! I plan on installing the trans with the body on the frame. Do you think there will be any problem of replacing it? let me know how the rest of your installation goes and what trans mount you use. Also, what rear gears are you plan on running?
Thanks for all your help,
Don

Bob Turner

80saintnick,

Since you have an '80, a four speed, and a removeable crossmember, the Richmond six is the EASIEST six speed swap out there. It is also the most expensive...... so you will have to decide.

I went with the following ratios:

2.77 1st gear
1.88 2nd
1.46 third
1.18 fourth
1 to one fifth
.62 sixth

I have the 3.08 rear but since I just dropped the 454 in, I think I need more rear gear, thus I am planning to build up a spare differential I have sitting around and put 3.55's in it.

I picked these ratios because they are spread out a bit but not too much. Your choice will depend on how the motor is set up, how much of an overdrive gear you want and what rear gear you are going to use.

For example, with the 3.08's, I am running 1750 rpms at 70 mph. This is too low of an rpm with the way the 454 is built. Thus, when I change out the gears to 3.55's, I will be running 2000 rpms at 70 mph, getting more into the power ranch of the motor.

If you are up for the challenge, take a look at this T56 six speed swap:
http://temp.corvetteforum.net/c3/gwhite75/index.htm

Bob