Engine/gearbox/final drive suggestions
Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
I have been asking for years, why can't someone make 3rd gear in my 4 speed 1:1, and add a 4th gear overdrive like .60:1 that would fit in the ST-10 box? My engine could easily do with 3rd gear being 1:1 with zero issues especially with the HP/Torque this engine makes now.
Could you imagine what would happen if someone sold the gears alone or offered to retrofit the 4 speed box for reasonable money ($1,000?). The 5/6 speed conversions would dry up overnight........
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
No.
I assume you are not interested in the $3k-5k bolt in 5 speed solutions offered in the aftermarket.
For bolt-in overdrive there are essentially two options. 1) find the super rare T50 5 speed from the Monza. Considering they are made of glass and will break when used with any engine over a 3 inch stroke and there are no replacement parts available no one in their right mind would use it. 2) have your current 4 speed box rebuilt using a steeper 1st gear. Then you can then have a 2.xx rear gear installed in the diff so with your 1:1 4th gear the revs drop.
There is nothing around that will bolt in inexpensively. A WCT5 is really the closest and is the way to go if trying to source from a salvage yard.
Of course the least expensive route is to use larger diameter tires.
Last edited by Dynra Rockets; Dec 15, 2017 at 03:59 PM.
Thread Starter
Intermediate
Joined: Nov 2016
Posts: 26
Likes: 1
Oh ok, I guess the wct5 is really my only option. The reason I was asking about the bolt in 4speed is because I’m in the UK, so sourcing a 5spd and getting parts will be a bit difficult. Thanks a bunch for explaining my options. I will probably do the wct5. So The most straight forward fit would be a gm 26spline v8 transmission, what gearing would suit my final drive?
Le Mans Master
Joined: Oct 2007
Posts: 7,453
Likes: 976
From: RI, Now Franklin/Nashville TN
Oh ok, I guess the t5 is really my only option. The reason I was asking about the bolt in 4speed is because I’m in the UK, so sourcing a 5spd and getting parts will be a bit difficult. Thanks a bunch for explaining my options. I will probably do the wct5. So The most straight forward fit would be a gm 26spline v8 transmission, what gearing would suit my final drive?
https://www.corvetteforum.com/forums...d-upgrade.html
Thread Starter
Intermediate
Joined: Nov 2016
Posts: 26
Likes: 1
Just used the online mph/revs gear ratio and what I’m getting is quite far off what the calculator is getting. Looks more accurate for a 3.55 rear?
Last edited by lucasl; Dec 16, 2017 at 01:06 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
He gets very good gas mileage and performance also.
I know you are dealing with a manual...but I was mentioning this so the gear ratio is not confusing you.
You can choose the ratio you want....to a point... as you have more than likely seen with the calculator
DUB
