View Full Version : 5 Speeds!

06-07-02, 07:14 PM
I need info on 5 speeds!

Makes, manufacturers and any info pertaining to swapping into a 4 speed C3 car.

It will need to handle 400 ft/lbs. of torque, 350HP.

I would like to do it without hacking the interior (i.e. console) too much, if at all.



06-12-02, 10:55 AM
The Richmond 5-speed comes to mind, which is based on the old Doug Nash unit. If you have the coarse-spline clutch disc, you have to switch to the fine-spline disc. A M-22 rear tranny yoke can be reused if you have one, otherwise you'll have to make the change. A Hurst 4+1 shifter is supposed to be a no-mod fit. Depending on budget, if you have the welded in crossmember, either switch to an aftermarket removable unit or a Corvette automatic crossmember. I'll search the web and see if I can find a documented conversion.


06-12-02, 10:59 AM

thanks for the tips! I'm filing away all of this info. I want to have as few hurdles as possible before I tare into everything... I wanna be driving!

If you come up with anything, much appreciated!


06-12-02, 11:54 AM
All I've found so far is a Richmond 6-speed Corvette conversion by someone who had a 5-speed. Here's the link for reference: http://home.att.net/~ncarboni/TrannySwap.html


06-12-02, 12:55 PM
TRANNY: Don't forget the factory transmission was not designed to handle 400 ft-lb of torque. The factory 4-speed in 1981 was rated at 300 ft-lb. A Richmond 5-speed will bolt right in without cutting the floorboard or changing the driveshaft. You will need a custom crossmember. They're rated at 450 ft-lb. The 3.28 first gear will give you great launches, while the 1:1 5th gear will leave you with good gas mileage, with your factory rearend gears. The 3.28 first gear combined with the factory 2.72 rearend is like a Muncie close-ratio with 4.05:1 rearend gears.

You'll need Acrobat Reader to view the first link properly. http://www.corvettefaq.com/redir.asp?site=370

Well, that's what I found. The information sounds fairly good, but maybe you want to conatct that guy from Finland.


06-12-02, 03:45 PM
Thanks, man.... the point of my 5 speed desire is lower cruising RPM's and a little better mileage. Do you know if Richmond or Tremec or someone builds one with a 5th OD??

06-13-02, 01:49 AM

This is perfect for my application. Multiplies torque well, overdrive between all gears and makes 4th/over.

The unit bolts on to the tailshaft and the greatest thing is that it can be remove if/when you want to sell your rig and they have a trade in policy.

Not my final choice, but after going to the page, it is VERY interesting.....


06-13-02, 04:21 AM
One of the member's here by the name of Redmist has the Gear Vendor's unit. I'm sure he is willing to share his experience. Here's a link about Tremec's vs. Richmond's 5-speed: http://www.tremectransmissions.com/faq.html

Q: How does the Tremec TR-3550 5 speed compare to a Richmond 5 speed?
A: Following are some comparisons:

The Tremec is a true overdrive transmission, where the Richmond has lower 2nd, 3rd, and 4th gears. All Richmonds have a 1.00 5th gear ratio, which suggests that you need a higher (numerically smaller) rear-end gear to achieve better fuel economy. Conversely, the Tremec offers a 0.62 or 0.83 ratio 5th gear ratio. Both transmissions offer basically the same 1st gear ratio, but the Tremec has a much broader range of gears. The Tremecís 5th gear ratio suggests that you have a lower (numerically higher) rear-end gear.

This link makes the comparison even further: http://www.tremectransmissions.com/5sp_comparison.html Just keep in mind that this is from a site that has interest in selling Tremecs. I guess it all depends on your specific needs.


p.s. I fixed the link to the 6-speed swap.