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StevenD57
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Yesterday after almost two years of on-again off-again design work, preparation, and fabrication I got to drive one of my Jensen-Healeys with a five speed transmission where the fifth gear is an overdrive ratio that lowers the engine speed while cruising on the highway. This is something I have been dreaming about for around five to ten years when I used to drive another one of my four-speed equipped Jensen-Healeys around on the freeways around Atlanta and was frustrated by what I felt was a very poor gearing design that artificially limited the comfortable highway cruising speed of the car.

So after all of this work and waiting, how was it? Well the initial experience is tempered by the lack of a gearshift knob that has the correct thread to match the Toyota W58 gearshift lever and a certain amount of harshness due to the transmission mount cross member still needing some work to correct some clearance problems around the back end of the Toyota transmission case. Plus I finished up the initial install only hours before having to prepare for an extended business trip so I only got to drive the car across town to visit Art DeKneef in Mesa AZ (southwest suburb of Phoenix) and then back to North Scottsdale so I did not get a whole lot of seat time as of yet and I am still a little new to the experience. So far I can see the 800 - 900 drop in RPM when cruising at 70MPH but I have not been able to enjoy any extended higher speed cruising in the 80 - 85 MPH ranges.

Technical details:
  • Toyota W58 transmission out of a late 1980's Toyota Supra
  • Lotus Excel bellhousing that Dan Eiland helped me obtain back in 2011
  • Altered the Lotus bellhousing to switch from hydraulic to stock JH cable operated clutch mechanism
  • Toyota Clutch kit (larger diameter clutch than stock JH one)
  • Re-drilled flywheel to use  dowel and bolt pattern to match the Toyota pressure plate
  • New driveshaft with Toyota slip yoke and longer length to account for the shorter overall transmission length but with correct flange to bolt up to input flange on the original JH four speed rear axle
Long term plan:
This first car is just the initial prototype of what I hope to be many more 5spd installations. I have two or three other cars I would like to convert to 5spd transmission setups. Plus I know there may be other JH owners who would also like to do the same conversion without spending huge amounts of money and time to source all of the required bits. Since the Lotus Excel bellhousing is such a hard piece to find here in the US (and possibly Europe), my current design efforts have been concentrated on altering the existing four speed bellhousings that are so relatively plentiful to accept either the Toyota W58 transmission or the Ford T9 transmission. I already have two 4spd bellhousings in the fabrication stages, one for each transmission, using fixtures that will enable the production of duplicates once the initial trial installations have been certified to work properly. I expect to enter into series production soon since I already have pre-orders from two folks who have already supplied me with their spare four speed bellhousings. Once I have the final designs of the altered bellhousing available they will be supplied on an exchange basis where the buyer will have to supply a stock four speed bellhousing
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Steve DuChene

Last edited on 03-03-2013 05:53 am by StevenD57

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StevenD57
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Wow! Great work Steven!
I'll have to look in the boneyard for a bellhousing.
I installed a rear end from a 5 speed car into my '73 to alter the cruising rpm's. The 4 speed gearing is a little funky with this setup but the power upgrades I've done have improved the torque so it drives fine.
Sander, these cars are not museum pieces, they are meant to be driven, modified, rebuilt, raced, and ultimately, scrapped.
Whoever has the most fun wins!
Kurt

StevenD57
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Here is some information on the gearing of the various transmissions (Thanks to Tim Engel for the figures):

..................... 1st ...... 2nd .... 3rd ..... 4th ..... 5th
Toyota W58......3.285.... 1.894... 1.275.. 1.00 ... 0.783

Getrag 245 ...... 3.37 ... 2.16 ... 1.58 ... 1.24 ... 1.00

Ford T9 ........... 3.36 ... 1.81 ... 1.26 ... 1.00 ...0.80

JH 4-spd ......... 3.12 .... 1.99 .... 1.30 .... 1.00

Last edited on 03-03-2013 03:14 pm by StevenD57

subwoofer
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Jensen Healey wrote:
Sander, these cars are not museum pieces, they are meant to be driven, modified, rebuilt, raced, and ultimately, scrapped.
Whoever has the most fun wins!
Kurt


Seconded!

There are some people who thrive on having the car as it looked in the showroom the day it rolled into the shop and consider a car an investment - a lot of the classic car mags seem biased to this view.

Then there is the other crowd, the ones that simply can't sit still and have to improve any problem areas as they are discovered. The purpose of a car is to drive, not sit in an air conditioned glass box. A driven car will eventually wind up with improvised solutions, improvements and more or less well thought out replacements for worn out bits when the old ones can't be repaired anymore.

As long as both crowds exist, the car can be seen both on the street and in museums.

Steve: If you do a T9 conversion kit, send me an email. The old 4-speed isn't in better shape than it has to be in...

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The first T9 bellhousing is at the machine shop waiting for some available CNC mill time. Once we have the T9 transmission flange bolt pattern on there then the design work on the location of the clutch fork pivot can be finalized. After that comes the first trial install. I have three T9 transmissions to choose from so I am all ready to go with the last part.

Last edited on 03-04-2013 06:00 am by StevenD57

jcdean
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Definately interested in the T9 converstion.  Thanks for taking the time and interest in doing  this.

roverman
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T5 vs T9 ? I plan to use an R154, in a future build,(big hp). Cheers, roverman.

StevenD57
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Unless you are planning on a big turbo I don't think you will be developing enough torque to exceed the capacity of the W58. Toyota spec'ed the R154 in the twin-turbo Supra cars. The NA 3.0L Supra's were just fine with the W58 torque capacities. The torque capacities I have seen for the two gearboxes is:

 W58: 300-350ftLb

R154: 450-550ftLb

BTW, Torque is what breaks gearboxes, not horsepower.

Last edited on 03-06-2013 11:13 pm by StevenD57

Randallclary@icloud.com
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So what ever happened to the T9 conversion? I am right in the middle or restoring my Mk 1 #13046 and going with a 2.2 L stroker crank, 10.5:1 compression pistons and ported head and want to reduce highway RPMs to a reasonable noise level. This looks like a great solution if it works.

subwoofer
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There have been bell housings for Vauxhall slant-4 to Rocket/T9 boxes on eBay, but none currently. AFAIK one of those should work, the 907 shares bolt pattern with the Vauxhall, right?

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So is the T9 mounting pattern, comparable to Ford/GM T5? If so, why not a T5? Plentiful and cheap, a good combination. roverman.

subwoofer
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T5s are rare in this part of the world, T9 and Rocket gearboxes are still plentiful. I don't think the T5 has the same bolt pattern, being a Borg-Warner box rather than a Ford (Europe) box.

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Joachim

Last edited on 09-10-2014 08:09 pm by subwoofer

Art DeKneef
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This is from Steve the last time I talked with him earlier this year.

He has moved to Colorado and does not have the bell housing with him there. The equipment was moved to a different place for modifications and I don't know the status of what happened after that.

I would guess the project is on indefinite hold until Steve gets the time to work on them again.

Art

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I am in Ohio now but I have not been able to locate a good CNC capable machine shop yet that seems interested in doing these small job lot type of things.

The last machine shop I had in Phoenix had time control issues (they would promise to have something ready in a week or two and then still not have anything done three or four weeks later). When I finally confronted the owner about this after having the project drag on for WAY too long he threw the project back in my face and refused to share any of the intellectual property I had developed.

I have two semi-finished bellhousings. One for the W58 and another for the T9. The T9 conversion bellhousing is somewhat simpler than the W58 due to the simple bolt pattern for the T9.

Last edited on 12-21-2014 05:03 am by StevenD57

DeDub
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I'm getting ready for a W58 swap in my track JH; my Getrag 5 speed has to be shifted with a soft hand to keep from grinding and probably only has a few more races in it. If a W58 bell housing becomes available, I'd like to know.

jdenglish
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Not exactly front page news but the 5-speed Getrag gear box rear end is not well suited for the W58. It's set up for a 1:1 final ratio. The W58 is a true overdrive in 5th. It took me one drive around the block to start looking for a 4-speed rear end.

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There seems to be some degree of consensus on both sides of the pond that the W58 gearbox does not work well with the taller 3.44 diff fitted to JH5s and GTs.

This is directly relevant to me at the moment, as my GT engine is being upgraded from factory standard to 907/912HC hybrid next month, and the workshop is trying to persuade me to ditch the Getrag 235/5 and upgrade to the W58 at the same time.

I am not keen on this for a number of reasons - i) I like the quirkiness of the dogleg 235/5 and its close ratios, ii) I don't want to have to incur even more expense by changing to a 3.73 diff to make the W58 work properly, and iii) I am concerned about the amount of modification required to make the W58 fit (my mantra is that all upgrades must be fairly easily reversible to factory spec).

On the other hand, the 1:1 5th gear in the 235/5, even with the taller 3.44 diff, is a real pain on the motorway, as 70mph = a rather noisy 3500rpm.

From a technical perspective, fitting a standalone overdrive unit would be the perfect solution, giving me a true overdrive top gear for the motorway while keeping the 235/5 close ratios for the winding stuff. But there simply isn't enough room in the transmission tunnel for an overdrive unit. I've thought about fitting the ZF S5-18 gearbox from the Lotus Sunbeam which has a dogleg shift pattern and can have a proper overdrive 5th gear, but it's very expensive in the UK and I think substantial modifications to the transmission tunnel would be needed to make the shift mechanism fit. I am sure fitting more soundproofing to the car would help reduce noise at cruising speed, but this would be dealing with the symptoms, rather than the cause.

More recently, I've been thinking about fitting the Getrag 265 and bell housing from the Lotus Eclat S2.2, which while rare is obtainable in the UK. While this is not a dogleg gearbox, it does have fairly close ratios 1st - 2.96, 2nd - 1.93, 3rd - 1.39, 4th - 1.00, 5th - 0.81 (NB these are different from the 1st and 2nd gear ratios for the 265 box in its BMW and Jaguar incarnations).

While these ratios are still fairly tall, they were considered to work pretty well in the Eclat S2.2 even with the optional taller 3.73 diff. My GT post engine upgrade should have more torque and bhp than the Eclat (which had the 912LC engine fitted). Plus I'm still on 185/70/13 tyres i.e. smaller than the 205/60/14s fitted to the Eclat. Relative to the W58 box, the gear change revs drops for the Eclat 265 are also fairly consistent and closer to the peak bhp (6500rpm) to peak torque (5000rpm) difference for the 912HC engine.

So I am hoping that the Eclat 265 gearbox could work well with the 907/912HC hybrid engine and 3.44 diff. I would also hope installing this box would be fairly easily reversible (if I wanted to go back to "matching numbers", or if my calculations are wrong and the 265 gearbox proves too tall in practice).

Any thoughts / comments would be greatly appreciated.

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My W58 conversion was the "close ratio" version and was completed in 2010.
It is an absolute pleasure to drive. The shift gate is tight and the individual gear ratios seem perfectly matched. (With the 4-speed rear end). Almost as if it was a CVT.

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I did not know there were versions of the W58 with different gear ratios. Although the R154 box fitted to the Toyota Supra turbo does have a different gear set. What are the ratios on your W58?

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I purchased a 2.2 crank, aluminum flywheel, W58 from Conversion Components in New Zealand in 2007 The close ratio gear box was an option. If I can locate the paperwork I might be able to shed some light on the ratios.

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Can you tell me what W58 trans you have that you like so well? Or what the donor vehicle was?

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My W58 was out of a late 1980's Toyota Supra.

DeDub
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Thanks. I'm sure there's plenty of those in my local PickNPull. I just got an email from Colin Dray in NZ saying he can still supply the bell housing, tho he neglected to tell me what it would cost.

StevenD57
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Here are the gear ratios that Tim Engel provided me a few years ago for the various transmission options:


Elite-Eclat ....... 1st ...... 2nd .... 3rd ..... 4th ..... 5th
Ford 4-spd .......3.16 ... 1.95 ... 1.41 ... 1.00 ... N/A
dif ratio 4.10 ...12.95 ... 7.99 ... 5.78 ... 4.10 ... N/A
dif ratio 3.73 ...11.78 ... 8.27 ... 5.26 ... 3.73 ... N/A <<

Elite-Eclat S1
Lotus 5-spd ..... 3.20 ... 2.01 ... 1.37 ... 1.00 ... 0.80
dif ratio 4.10 ...13.12 ... 8.24 ... 5.62 ... 4.10 ... 3.28 <<
dif ratio 3.73 ...11.94 ... 7.50 ... 5.11 ... 3.73 ... 2.98

Elite-Eclat S2.2
Getrag 265 ...... 2.96 ... 1.93 ... 1.39 ... 1.00 ... 0.81
dif ratio 4.10 ...12.14 ... 7.91 ... 5.70 ... 4.10 ... 3.33 <<
dif ratio 3.73 ...11.04 ... 7.20 ... 5.18 ... 3.73 ... 3.03

Excel
Toyota W58......3.285.. 1.894.. 1.275.. 1.00 ... 0.783
dif ratio 4.10 ...13.468.. 7.765.. 5.227.. 4.10 ... 3.210
dif ratio 3.73 ...12.253.. 7.065.. 4.756.. 3.73 ... 2.920

Lotus Talbot Sunbeam
Sunbeam ZF .... 3.42 ... 1.94 ... 1.39 ... 1.10 ... 0.80

dif ratio 4.10 ...14.02 ... 7.95 ... 5.70 ... 4.51 ... 3.28
dif ratio 3.73 ...12.76 ... 7.24 ... 5.18 ... 4.10 ... 2.98

Jensen-Healey Mk II  5-spd
Getrag 245 ...... 3.37 ... 2.16 ... 1.58 ... 1.24 ... 1.00
dif ratio 4.10 ...13.82 ... 8.86 ... 6.48 ... 5.08 ... 4.10
dif ratio 3.73 ...12.57 ... 8.06 ... 5.89 ... 4.63 ... 3.73 <<
dif ratio 3.45 ...11.63 ... 7.45 ... 5.45 ... 4.28 ... 3.45
............ 3.45 = stock JH 5-spd final drive ratio

Merkur XR4Ti
Ford T9 ........... 3.36 ... 1.81 ... 1.26 ... 1.00 ... 0.80
dif ratio 4.10 ...13.78 ... 7.42 ... 5.17 ... 4.10 ... 3.28
dif ratio 3.73 ...12.53 ... 6.75 ... 4.70 ... 3.73 ... 2.98
....................... 1st ...... 2nd .... 3rd ..... 4th ....5th

Honda ............. 1st ... 2nd ... 3rd ... 4th ... 5th ... 6th
S2000 6-spd ... 3.13 ..2.04 ..1.48 ..1.16 ..0.97 ..0.81
dif ratio 4.10 ...12.83.. 8.36.. 6.06.. 4.75.. 3.97.. 3.32
dif ratio 3.73 ...11.67.. 7.61.. 5.52.. 4.33.. 3.62.. 3.02

Mazda Miata from recent Mazda website
Miata 6-spd ..... 3.81.. 2.26.. 1.64.. 1.18.. 1.00.. 0.83
dif ratio 4.10 ...15.64.. 9.27.. 6.72.. 4.83.. 4.10.. 3.41
dif ratio 3.73 ...14.23.. 8.43.. 6.12.. 4.39.. 3.73.. 3.10

Mazda Miata 6-spd from
http://members.aol.com/solomiata/Drivetrain.html
Miata 6-spd ..... 3.76.. 2.27.. 1.64.. 1.26.. 1.00.. 0.84
dif ratio 4.10 ...15.42.. 9.30.. 6.74.. 5.15.. 4.10.. 3.46
dif ratio 3.73 ...14.02.. 8.46.. 6.14.. 4.69.. 3.73.. 3.14
....................... 1st ... 2nd ... 3rd ... 4th ... 5th ...6th

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DeDub wrote:
Thanks. I'm sure there's plenty of those in my local PickNPull. I just got an email from Colin Dray in NZ saying he can still supply the bell housing, tho he neglected to tell me what it would cost.

Ha ha! From what I've read, he charges your credit card immediately and then is unresponsive for months and months. When you finally try to reverse the charge, it's too late, so you get to wait some more. He's been using health issues as an excuse.

Make sure he has the product in hand before paying any money!

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If this guy is as shaky of a person as you are saying then only way for someone not in NZ to do that would be have an assistant in NZ go there with cash and only hand it over when the actual product is produced. That assistant would have to know what a Jensen-Healey or Lotus 907 bellhousing looked like so they would know for sure they were getting the right product.

Jensen Healey
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I don't think Colin is intent on defrauding people, just that he has had some reliability issues. I believe that he would answer honestly if asked.
He certainly has provided a nice kit to the community in the past.
We do slow down as we inch up in years. It was sad to see Caribou Tops become so unreliable. They made a fine product but the delivery times got unbearable.

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After a great deal of research on other options, I have come to the conclusion that there is no easy way of keeping a Getrag box in my GT while having a proper overdrive 5th gear. So I have decided to install a Toyota W58 box out of a Lotus Excel, in parallel with upgrading the engine to 907/912HC hybrid. I'll retain the original 3.45:1 axle.

This raises a further question about the speedo cable. For those of you who have installed the W58 box, did you need a new cable with a different coupling at the gearbox end, and/or to recalibrate the Smiths speedo?

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Nigel,
The 3:45 rear end IMHO is too tall. I made the W58 conversion and stayed with that ratio. One trip around the block and I went shopping for a 3:73

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Hi JD

The tall back end remains a concern. I'm hoping that the extra power and torque of the 907/912HC hybrid engine will compensate for the tall gearing. But we'll see. These things are a matter of taste, and I'd prefer my GT to live up to its name as opposed to being an out and out street racer...

If I do need to change the back end, I'll probably go for an Atlas axle out of a Ford Cortina / Capri, rather than the Viva HC 3.73:1 axle. The Ford unit is more robust, easier to come by, and parts and different ratio CWPs are widely available.

Best wishes,
Nigel

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Nigel
What sorts of things will you have done to the bottom end of the 907 when you stretch it to the 2.2L

I know LotusBits, Tim Engel and other experts say things like extra dowels on the girdle are a good thing to do so the girdle plate does not move around. The original 907 as used in the Jensen Healey only had two dowels around the main girdle studs to locate it but in later years they increased this number. I think they also went from 6mm studs to 8mm studs around the outside edge if the girdle as well. I could be wrong on this last item though (I.E. the JH 907 motors might have had 8mm studs)

Last edited on 02-21-2015 06:50 pm by StevenD57

NigelK
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Hi Steven

LotusBits are doing the conversion, and I'm not sure what (if any) mods Mike intends for the bottom end. He hasn't mentioned any to me. The bottom end of my engine is not the original A74 - a PO replaced it with a late 1975 bottom end from a Lotus Elite. So hopefully it'll be strong enough.

But let's see what comes up when the actual rebuild starts next week. Maybe Mike will suggest some bottom end strengthening when the engine is stripped.

Today's pleasant "surprise" came when the engine and gearbox were pulled and split, revealing a completely disintegrated spigot bearing, a damaged input shaft, and only 4 properly tightened clutch plate screws. I suspect repairing the input shaft could get rather expensive, so just as well I'm having the W58 fitted!

Best wishes,
Nigel

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What is he doing about the clutch actuation? The Excel was a hydraulic clutch verses the mechanical cable type on the JH. I used an Excel bellhousing and I had to enlarge the hole for the arm to stick out and locate a pivot pin over on the other side of the bellhousing (on the inside).

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He's converting the clutch from hydraulic to cable actuation. I can't give you anymore detail, but would be happy to provude photos of the work and pass on questions to Mike. I am not a technical expert - I did not even know what a spigot bearing was before this morning...

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I did a W58 in my JH5, the first time I drove it with the 3:45 axle I went hunting for a 3:73. Now that it's in the car it feels much better; 1st through 4th are fine for around town and 5th is much better on the Interstate. I did my swap with a bellhousing from LotusBits, I had the stock J-H flywheel redrilled for a Toyota Celica pressure plate. The spigot bearing was not compatible with the Toyota trans so I made a new one out of bronze Oilite. The clutch release mechanism uses the stock J-H clutch cable and a modified J-H release fork which allows use of a Celica release bearing. The shifter for the W58 was too far forward so I cut the stock shift extension in half and lengthened it, then cut the Toyota shift lever off and welded a J-H lever to the remaining stub. The shifter comes out in the center of the stock tunnel opening and doesn't interfere with anything.

Last edited on 03-22-2015 09:53 pm by Jensenman

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Hi Jensenman

Did you have a stock 907 in your JH5? Or had you already upgraded the engine when you decided that the back end was too tall? I am beginning to feel I might need to start looking for a 3.72:1 Vauxhall Magnum cwp set...

Best wishes,
Nigel

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Stock 907 with Dellortos and a Crane ignition. It was pretty obvious on the first test drive the 3:45 rear axle did not allow the car to move out with authority from a dead stop. The 3:73 fixed that.

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By the way, about the speedometer cable: I don't know about European transmissions but over here there's a limited number of speedometer gears for the W58. I had to go with (IIRC) a 31 tooth gear, to make that work I had to make an eccentric housing for the speedometer drive. If I use my GPS, the 31 tooth drive gear combined with the 3:73 rear the speedometer reading is within 2 mph of the GPS reading. I then used a Mazda RX7 speedometer cable and put the J-H end on its housing.



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