I have a 72 Stingray with a stroked 350 and a stock 4 speed that I want to swap out for a 'TKO-600 5 SPEED OD TREMEC TRANSMISSION'. Problem is - who should I purchase from? I have a shortlist of suppliers and I'm open to any suggestions. These are my current choices: 1) Eckler's Corvette's 1968-1976 Corvette 5-Speed Transmission Conversion Kit Tremec TKO 600 Street / Strip Edition American Powertrain $4,460.99 Kit

https://www.ecklerscorvette.com/1968...owertrain.html

2) Corvette Central 68-76 TKO-600 5 SPEED OD TREMEC TRANSMISSION MANUAL TO MANUAL (ND) $3,799.00

https://www.corvettecentral.com/c3-6...mission-533220


3) Zip Corvette’s 68-79 TKO 600 5-Speed Transmission Conversion (Manual to Manual) $3,699.99

https://www.zip-corvette.com/68-79-t...to-manual.html

There is a substantial difference in the price - but - what differences should I expect in the kits? I'm asking for experienced help as well as recommendations - links would be so very much appreciated.... Thanks in advance.

 

Silver Sport transmissions I used them for the TKO 600 in my 79 Corvette . They are very helpful and the kit had everything I needed .It is the best thing I did to my car.A lot of fun to drive.

 

I would recommend Silver State. You pay for what you get. I'm safety conscious, so I went with all SFI stuff. Blow proof bell housing, flywheel, and PP.

I really believe in lighter weight flywheels. 22 pound 168 tooth 11 inch is a good idea. 168 tooth requires a mini starter. I hope that you have an internally balanced stroker motor.

Second thing is gearing. IMO if your rear end is less than a 3.73 I would recommend the .82 OD.

 

Also agree. I had ended up going with the Richmond 5 speed o.d, and that comes with .77 5th. Ive got 3.55's. Basically this cut about 750 rpm out of my cruise, and is not a dramatic drop from 4th to 5th, but enough to make the car more comfortable to drive (someday Im going to put it back in the car). The .64 o.d is a HUGE step from 4th gear, and could easily lead to awkward up and down shifts in a normal traffic setting if you don't have enough gear.

 

The large drop to 5th is the reason that I figured out a T-56 Magnum swap back in 2011 (before kits were available). Now, I have a .82 5th and .63 6th. Perfect,

As for the OP, go with Silver Sport, American Powertrain or one of the other Tremec swap firms. That way, you avoid the Corvette tax and can get support from the folks who made the kit. Ecklers, Corvette Central, and Zip are just reselling someone else's kits and won't be able to answer technical questions if you run into issues.

 

All the suppliers make their own shifters for the TKO. The American Powertrain one uses a center bolt affair that I have seen customers complain that the "bolt comes loose". The C3 shifter handle uses a offset "L" shape.
The SilverSport has their own proprietary C3 shifter design, which is not available separately, and does require them to make a slight machining modification to the trans to install. If you look close you can see they have a box that sticks out to the left of the trans. The advantage of this design is the C3 shifter handle goes straight down, and works better. The shifter "ball" joint is slightly outside the original trans.

Much better/stronger/durable C3 shifter design in my opinion.

 

Wow, thanks for all the info. I have contacted Silver Sport for a quote. https://shiftsst.com/blog/post/1968-...ctfit-kit.html. A little info on my current car - the 383 is internally balanced and has a 'big mother Thumper camshaft'. The motor has aluminum heads and idles good (a little choppy). The motor was dyno'd with 500 hp and 550 'tq and it was all in below 6k rpm. The car comfortably idles under 1k. The rear gear is a factory 323 (I think). The rear diff is stock Big Block for the 1972 Vette. I currently have a Muncie 4 speed in the car. The gearing info shared is particularly of interest considering the research I have done on this forum. There seems to be several schools of thought. I'm hearing the 2.87, 1.89, 1.28, 1.00, 0.64 or 2.87, 1.89, 1.28, 1.00, 0.82 from some as well as the .63 for 5th (od). I still need a little more insight before choosing the od gear. All help is very much appreciated

 

You can try Forte's Parts Connection in Framingham MA. He was selling Tremecs for GM vehicles BEFORE Tremec offered them. He had input shafts manufactured, and the case re-drilled so they would bolt into GM products. He is/was a racer and is extremely knowledgeable. I bought my first tremec from him in 1996 and have never looked back.

 

IMO there is no better place than Silver Sport with their Perfect Fit kit.
I also went with their dual disc clutch recommendation and changed to a hydraulic clutch pedal. SOOOOOO smooth!!!!!
I love it.

 

Do you have any specific info about exactly what you had to do to make it fit? Maybe a couple of pics of the finished job or anything you might be able to offer?

 

I wouldn't get it from WHO, Trump is going to pull their U.S. funding for caving to the China propaganda machine.

There are plenty of stateside vendors to chose from.

 

LOL...that's just funny, "I don't care Who you are".....so says the Cable guy.....

 

Dont get the .050 OD have it in my T56 even with 4.11s almost unusable cant stand it.

 

Sounds like you are picking a very similar combo as me.
You could run either of two combos with the 3.23. I'm going to do the TKO500 with it's 3.27 1st and .68 OD. 10.6 gear overall in 1st and 1950 rpm cruise.

Another option is the TKO600 with the 2.87 1st and .82 OD. Not quite as big a gear spread. 9.3 in 1st and 2344 rpm cruise.

How low of a speed does your 383 comfortably cruise at now? You could try that before you buy. Some combos do not like a 1800 rpm cruise. That hot of a 383 may not either. I know my LT-1 would not. But my milder 454 will.

All the gear drops are larger than a Muncie CR. Those drops are about 800 rpm and the TKO varies a little but are around 1100-1200.

Silversport said the TKO 500's 500 lb torque rating will not be stressed even with my 555 TQ BB 454. (Muncies are only guesstimated as being "rated" somewhere in the low-mid 400s)

Enjoy the spreadsheet.

 

The charts are a HUGE help.....Thanks soo much for sharing. Did you put that together or was it given to you by one of the Transmission vendors? It's excellent!!

 

I have a Quote from Silver Sport - it's extremely competitive and I will be purchasing from them. I'm very curious about this 'minor' modification to the console for the TKO-500 shifter. Can anyone outline the changes needed?

 

The charts are my original work. Like you I was very confused by all the different ratios and possible combinations involved. That's my way of making sense of it all.
I wanted to look at:

• overall first gear ratio
• mph in each gear change
• rpm drop at each gear change
• and especially rpm at cruise speed.

Glad they helped you!

However real world feedback is just as important.

Still not sure if my 454 will like cruising at 1800 rpm. Just cause I haven't driven it yet. 5th gear may wind up as a wait until 60 or 65+ gear. I'm OK with that. My daily driver is a no top gear til 60 car. I just hope I pick the right combo I'll be happy with the first time. Rather just build this once.
I have two current E.F.I. cars that cruise happily at 60-70 at 2000 from the factory with mild V6s. But not enough TQ to do any lower. Double the cubes should solve that!

But I absolutely know that my LT-1 I drove for 27 years would not like that cruise rpm. It had a much stronger cam, (I ran the 30-30). I never tested low rpm cruise on that, but I am guessing it would have liked something no lower than say 2300ish? That cam kicked in Hard at 3300. And the engine pulled to 7200. I never ran anything less than a 3.55 rear on that one. So it would hum along happily at say 2800-3000 more often than not. How much lower than that I can't say. I know it cruised very well at 60+ (2500) but don't remember how well it cruised at 50 (2100). IIRC it was ok but probably not great. The engine liked a 3000 hwy cruise (75) but the oil temp would just keep climbing to silly levels. Think I saw 350+ once. I basically had to keep it under 70 (2800) on the interstate due to oil temps. Still got 15 mpg with it so not bad.

That's my MPG target with the 454. With 1000 less rpm I think it's completely doable. This BB C3 has some road trips in it's future. When's the last time you saw that? My fathers 472 Caddy got 15 mpg hwy all the time so I think I can do that, or maybe better.

 

I love the tko. The 3.27 first gear is very low though anecdotally speaking. Those charts will give you good guidance as long as tire size is included. I did something similar about 10-12 years ago to minimize my drag strip shifts in relation to my engine red line. Sorry I didn’t read those charts but without that info it would be hard to make a good decision.

 

I have the TKO 600 with the .64 OD behind a 427 small block in my '79 with 3.55 gears. If I had it to do over, I might choose the .82 OD. Its a big drop from 4th to 5th. 5th is purely an overdirve for use when cruising on the highway. Its good for mileage, but it just doesn't feel like it fits with the rest of the gears, if that makes any sense. Its like 1-2-3-4.....wait for it....5th. Also I got my transmission from Modern Driveline, although I put the rest of the parts together myself. The shifter lines up perfectly with the console, although I did have to modify the hole in the floor because I was converting from an automatic. I used the Hurst shifter handle for my car and the shifter ball is in a perfect position. No modification to the console was necessary.

 

I have decided to pull my factory motor (stroked 350) and trans and store them for a "numbers matching option in the future". I'm having a 434 Small Block built. I spoke to the machine shop today and the gears are rolling. The 434 will be in the 600 - 650 hp range with 'hopefully' impressive torque numbers. I'm also planning for a little juice (150-200hp plate) just for grins and giggles. The Silver Sport TKO is a must now. I'm pretty certain my OD will be the .82 from the input given in this thread and the very helpful charts offered by leigh1322. The cam hasn't been chosen yet but I'm being a little conservative while considering the torque capability of this little mouse. My actual goal with the combination is around 650hp on pump gas. I'm going to use a dual-plane manifold with hopes of keeping the reves no higher than 6500. That is going to take some clever building but the folks I have chosen are up to the task. .......The transmission --- I still have some questions; Does anyone have experience with Silver Sport's " Quote" "[ NEW SUPER DUTY 621 Reproduction GM bellhousing re-engineered by SST with thick wall
titanium-aluminum alloy construction and CNC machined in-house. For small/big block Chevy engines and 168 tooth flywheel. Best 621 reproduction bell on the market- MADE IN USA! 6.29inch depth]" ? I'm thinking about purchasing this with the transmission. I sure do appreciate the input you wonderful folks have offered to this little post, it has been soooooo very useful and helpful!