Converting from auto to 5spd question
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,185
Likes: 9,321
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
You will have to dig through this pile. They dont let you use numbers in the searches apparently 
https://www.corvetteforum.com/forums...rchid=85037018
https://www.corvetteforum.com/forums...rchid=85037018
https://www.corvetteforum.com/forums...rchid=85037018
https://www.corvetteforum.com/forums...rchid=85037018
Team Owner
Joined: Jul 2004
Posts: 40,381
Likes: 789
From: Redondo Beach, California
Cliff's notes:
I bought a Tremac 5 speed configured with the shifter in a C3 correct position. You have a removeable auto transmission crossmember so this greatly helps with transmission install. If you've a 3.73:1 or numerically higher differential, the Tremac is easily the way to go. For a 3.08:1,or lower, you'll need a Richmond 5 speed. My opinion about diff gearing. Opinions may differ..
Need to have a frame fitting welded to the frame to support the "Z bar".
Installing the clutch support mechanism on the inside of the firewall will just be sooooo much fun,
I bought a Tremac 5 speed configured with the shifter in a C3 correct position. You have a removeable auto transmission crossmember so this greatly helps with transmission install. If you've a 3.73:1 or numerically higher differential, the Tremac is easily the way to go. For a 3.08:1,or lower, you'll need a Richmond 5 speed. My opinion about diff gearing. Opinions may differ..
Need to have a frame fitting welded to the frame to support the "Z bar".
Installing the clutch support mechanism on the inside of the firewall will just be sooooo much fun,
Team Owner
Joined: Jul 2004
Posts: 40,381
Likes: 789
From: Redondo Beach, California
It's your decision, I'm partial to the Tremacs. They have a nice shift feel with short shift throws. They use the same gear shift lever of a standard factory C3. Heres the gear ratios for the TKX-5 speed
Wide Ratio: 3.27, 1,98, 1.34, 1.00, 0.72
Close Ratio: 2.87, 1.89. 1.28, 1.00, for 5th gear you get a choice of 0.68 or 0.81
Don't know what Muncie you have now, but it could be a M20 wide ratio, which is a common Muncie sold up until 1975.
M20 Wide Ratio: 2.52, 1.88, 1.46, 1.00
The close ratio TKX-5 speed gear ratios pretty much approximate what I'd guess is your present Muncie in the first 4 years and then gives you an overdrive in 5th. In 5th gear, you get a choice. For a 3.36, The 0.68 option gives you an effective rear end of 2.28 (not acceptable) or the 0.81 gives you an effective rear end of 2.72. The effective diff ratio of 2.72 gives you an cruise rpm drop of 20%.
The wide ratio 3.27 gives you a more effective launch rpm, but I think the cruise overdrive ratio (5 gear) may be numerically too low. Since the Muncie approximates your current tranny in the first four gears, and gives you a nice 30% drop in cruise rpm. Maybe you'd like this. But it's your choice.....maybe some other readers have an opinion.
https://shiftsst.com/blog/post/1968-...ctfit-kit.html. Talk to Silver Sport about a recommendation.
Wide Ratio: 3.27, 1,98, 1.34, 1.00, 0.72
Close Ratio: 2.87, 1.89. 1.28, 1.00, for 5th gear you get a choice of 0.68 or 0.81
Don't know what Muncie you have now, but it could be a M20 wide ratio, which is a common Muncie sold up until 1975.
M20 Wide Ratio: 2.52, 1.88, 1.46, 1.00
The close ratio TKX-5 speed gear ratios pretty much approximate what I'd guess is your present Muncie in the first 4 years and then gives you an overdrive in 5th. In 5th gear, you get a choice. For a 3.36, The 0.68 option gives you an effective rear end of 2.28 (not acceptable) or the 0.81 gives you an effective rear end of 2.72. The effective diff ratio of 2.72 gives you an cruise rpm drop of 20%.
The wide ratio 3.27 gives you a more effective launch rpm, but I think the cruise overdrive ratio (5 gear) may be numerically too low. Since the Muncie approximates your current tranny in the first four gears, and gives you a nice 30% drop in cruise rpm. Maybe you'd like this. But it's your choice.....maybe some other readers have an opinion.
https://shiftsst.com/blog/post/1968-...ctfit-kit.html. Talk to Silver Sport about a recommendation.
Last edited by 68/70Vette; Jul 2, 2021 at 01:37 AM.
Le Mans Master
Joined: May 2007
Posts: 5,021
Likes: 1,120
From: North tonawanda NY
It's your decision, I'm partial to the Tremacs. They have a nice shift feel with short shift throws. They use the same gear shift lever of a standard factory C3. Heres the gear ratios for the TKX-5 speed
Wide Ratio: 3.27, 1,98, 1.34, 1.00, 0.72
Close Ratio: 2.87, 1.89. 1.28, 1.00, for 5th gear you get a choice of 0.68 or 0.81
Don't know what Muncie you have now, but it could be a M20 wide ratio, which is a common Muncie sold up until 1975.
M20 Wide Ratio: 2.52, 1.88, 1.46, 1.00
The close ratio TKX-5 speed gear ratios pretty much approximate what I'd guess is your present Muncie in the first 4 years and then gives you an overdrive in 5th. In 5th gear, you get a choice. For a 3.36, The 0.68 option gives you an effective rear end of 2.28 (not acceptable) or the 0.81 gives you an effective rear end of 2.72. The effective diff ratio of 2.72 gives you an cruise rpm drop of 20%.
The wide ratio 3.27 gives you a more effective launch rpm, but I think the cruise overdrive ratio (5 gear) may be numerically too low. Since the Muncie approximates your current tranny in the first four gears, and gives you a nice 30% drop in cruise rpm. Maybe you'd like this. But it's your choice.....maybe some other readers have an opinion.
https://shiftsst.com/blog/post/1968-...ctfit-kit.html. Talk to Silver Sport about a recommendation.
Wide Ratio: 3.27, 1,98, 1.34, 1.00, 0.72
Close Ratio: 2.87, 1.89. 1.28, 1.00, for 5th gear you get a choice of 0.68 or 0.81
Don't know what Muncie you have now, but it could be a M20 wide ratio, which is a common Muncie sold up until 1975.
M20 Wide Ratio: 2.52, 1.88, 1.46, 1.00
The close ratio TKX-5 speed gear ratios pretty much approximate what I'd guess is your present Muncie in the first 4 years and then gives you an overdrive in 5th. In 5th gear, you get a choice. For a 3.36, The 0.68 option gives you an effective rear end of 2.28 (not acceptable) or the 0.81 gives you an effective rear end of 2.72. The effective diff ratio of 2.72 gives you an cruise rpm drop of 20%.
The wide ratio 3.27 gives you a more effective launch rpm, but I think the cruise overdrive ratio (5 gear) may be numerically too low. Since the Muncie approximates your current tranny in the first four gears, and gives you a nice 30% drop in cruise rpm. Maybe you'd like this. But it's your choice.....maybe some other readers have an opinion.
https://shiftsst.com/blog/post/1968-...ctfit-kit.html. Talk to Silver Sport about a recommendation.
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
If you go with a Richmond you might want to look into using a Long's shifter instead of a Hurst. It is pricey, but it was a huge improvement.
https://www.gforcetransmissions.com/...peed_Trans.pdf
https://www.gforcetransmissions.com/...peed_Trans.pdf
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Thread Starter
Racer
Joined: Nov 2004
Posts: 432
Likes: 89
From: Georgia
Yes I currently have the stock TH400 and thinking of making it more fun to drive without making any irreversible changes.
I hope silver sport can help me with the gear ratios. Seems like a complete kit is the way to go with hydraulic clutch cylinder add on
I hope silver sport can help me with the gear ratios. Seems like a complete kit is the way to go with hydraulic clutch cylinder add on
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I bought the complete kit for under $5000. With upgrades like blow proof bell housing, block saver plate, 22 pound SFI steel 168 tooth flywheel, 11 inch clutch, easy on the leg 1100 hp clutch/pressure plate. chromemoly drive line with billet main caps.
i advice against Hydro assisted clutches. It ruins all the petal feel and it's another failure point.
i advice against Hydro assisted clutches. It ruins all the petal feel and it's another failure point.
Melting Slicks
Joined: Oct 2001
Posts: 2,064
Likes: 1,382
From: Halifax, Nova Scotia, Canada
Melting Slicks
Joined: Jun 2011
Posts: 3,114
Likes: 598
T56 Magnum Install 78 Corvette. - CorvetteForum - Chevrolet Corvette Forum Discussion
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
Here's my Richmond 6 speed swap..https://www.corvetteforum.com/forums...am-change.html
Best mod on the ol vette ..Most expensive too! Well worth the time & $$ ..The Richmond is same length as the TH350 used the same driveshaft just a new yoke on the trans output..
Pedal assembly was the worst part of the job ..Z Bar bracket on the frame was flexing ,got a stronger one from a forum member.Didn't weld the bracket I drilled and tapped the frame .
Also used a Gforce Trans crossmember .If you have the funds go for a complete kit save you the hassles chasing down parts...Good luck with the project!
Best mod on the ol vette ..Most expensive too! Well worth the time & $$ ..The Richmond is same length as the TH350 used the same driveshaft just a new yoke on the trans output..
Pedal assembly was the worst part of the job ..Z Bar bracket on the frame was flexing ,got a stronger one from a forum member.Didn't weld the bracket I drilled and tapped the frame .
Also used a Gforce Trans crossmember .If you have the funds go for a complete kit save you the hassles chasing down parts...Good luck with the project!
Last edited by iokepakai; Jul 5, 2021 at 12:51 PM.
Pro
Joined: Nov 2017
Posts: 587
Likes: 49
From: Belgium
Depends what you want to do.
you can go the easy and expensive way ( tremec) they're virtually a direct fit. Same driveshaft, crossmember,... so just cut a hole for the shifter, change the center console plate , add a clutch, bolt or weld the Z bar bracket and wire up the reverse.
Or, do like me and buy a T5 out of a late 80's camaro and get a shorter driveshaft and modify your crosmember. All depends on your skill level and how much your wife let's you spend on the car 😉
you can go the easy and expensive way ( tremec) they're virtually a direct fit. Same driveshaft, crossmember,... so just cut a hole for the shifter, change the center console plate , add a clutch, bolt or weld the Z bar bracket and wire up the reverse.
Or, do like me and buy a T5 out of a late 80's camaro and get a shorter driveshaft and modify your crosmember. All depends on your skill level and how much your wife let's you spend on the car 😉
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,053
Likes: 4,402
From: Marlton NJ
I recommend the TKX CR box. 2.87 1st .68 OD
With a 3.36 you'll have 10:1 in first gear, very peppy.
OD will give you 2050 rpm at 70. Very relaxed Hwy cruising.
But probably means you will be in 4th til 60 or more til you got to 5th.
That's not as big a deal as some say, it's what my street car does everyday.
My buddy geared his way different with 4.11s and same trans. He can use 5th gear from 50 rpm up. But has so much 1st it just lights em up very easy.
I just got my TKX last wednesday!
It was 8 week delivery from Silversport.
And the CR/.68 is the only version Tremec is making right now anyway, the other 2 gearsets have an unknown delivery date.
Here is a spreadsheet you can play with ratios if you like:
With a 3.36 you'll have 10:1 in first gear, very peppy.
OD will give you 2050 rpm at 70. Very relaxed Hwy cruising.
But probably means you will be in 4th til 60 or more til you got to 5th.
That's not as big a deal as some say, it's what my street car does everyday.
My buddy geared his way different with 4.11s and same trans. He can use 5th gear from 50 rpm up. But has so much 1st it just lights em up very easy.
I just got my TKX last wednesday!
It was 8 week delivery from Silversport.
And the CR/.68 is the only version Tremec is making right now anyway, the other 2 gearsets have an unknown delivery date.
Here is a spreadsheet you can play with ratios if you like:
Last edited by leigh1322; Jul 5, 2021 at 11:06 PM.
Burning Brakes
Joined: Nov 2011
Posts: 1,170
Likes: 201
From: Willoughby Ohio