# transmission



## artjumps (Dec 10, 2021)

I know this is probably a wore out subject but I'm gonna go for it anyway. I will be upgrading the transmission in my 66 goat in the future. It currently has the 2 speed auto, and I would like to switch to an overdrive. My first consideration is to go with the 200r4. The car is mostly stock, 389, unsure of the gearing at this time but believe it to be fairly standard, maybe 3.23, 3.36, 3.55, not certain though at this time. It has the 4 barrel sniper efi. I do not plan to change anything as far as engine size or horsepower upgrades. Will mainly use it as an occasional in town cruiser, car shows, but would also like to comfortably take it on the freeways if need be. So that is why the 200r4 comes to mind. What I was wondering was if any others out there have made that upgrade, and if so what kind of experience you have had or if there are any suggestions as to quality builders or dealers for that particular trans. Thanks so much.


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## geeteeohguy (Feb 2, 2008)

The 200r4 is the best fitting of the auto overdrives for your application...you can even use your original driveshaft. The set-up of the throttle valve cable is critical on these transmissions and you will need to wire in a means to turn on and off the locking torque converter, which is electronically controlled with a solenoid. Gearstar sells an upgraded unit as do other outfits...check on line. Whether you install a non overdrive TH 350 (also a bolt-in) or the 200R4, your car will feel like it gained 100 horsepower due to now having a decent first gear ratio. The 1.76 low gear on your current ST300 is a super impairment to performance. You will get better performance and economy with a TH350 or 200. Many install 700R4's and 4L60's, etc., but for your application, the 200r4 built to handle the 389 is the way to go, IMO. The car will pull much harder off the line, will get much better fuel economy, run cooler, run quieter, etc. There is no downside to the upgrade and it's the best performance improvement for the buck you can do on your car. Keep us posted.


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## artjumps (Dec 10, 2021)

geeteeohguy said:


> The 200r4 is the best fitting of the auto overdrives for your application...you can even use your original driveshaft. The set-up of the throttle valve cable is critical on these transmissions and you will need to wire in a means to turn on and off the locking torque converter, which is electronically controlled with a solenoid. Gearstar sells an upgraded unit as do other outfits...check on line. Whether you install a non overdrive TH 350 (also a bolt-in) or the 200R4, your car will feel like it gained 100 horsepower due to now having a decent first gear ratio. The 1.76 low gear on your current ST300 is a super impairment to performance. You will get better performance and economy with a TH350 or 200. Many install 700R4's and 4L60's, etc., but for your application, the 200r4 built to handle the 389 is the way to go, IMO. The car will pull much harder off the line, will get much better fuel economy, run cooler, run quieter, etc. There is no downside to the upgrade and it's the best performance improvement for the buck you can do on your car. Keep us posted.


Thanks for the feedback, I appreciate the reply.


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