ST300 transmission Shift Kit? (66 Article)

[jmos4]

Hi all,

I've been doing so research on this 66 Buick article on modifying the valve body plate and wanted to know if anyone here has done this modification, as the article I have has a very hard to decipher picture on what hole needs to be opened from .090 to .125.

Regards,

[jmos4]

Hi all again,

Well after some searching on the internet I did find this on Russ Martins web site.

Also found out that there are 2 different valve body gaskets as mine did not have the A & B holes. So I did drill out hole C to 1/8" so will see if it helps.  Also found out that Trans-n-go was formerly Research from the article.  http://www.transgo.com/contact.html

As I had to call them to verify which gasket to use.

Regards,

[GreatScat1965]

Good stuff, I'll throw my 2 cents worth. When I bought my GS in 1994 it had a freshly built ST300 by someone in the Upstate NY area. Supposedly similar modifications were done to it. I can't verify that but the ST300 ST400 Guru at the time was Mark DeConti. He made a band adjustment based on old information like this and when he was done that was the best 2 speed I've ever driven. I like the ST300 and personally the biggest issue is no one seems to be able to get Idle micro switch set properly. A "gadget" switch as Pops Kennedy referred to it as is a must have as well. Rob (Stage 1 Performance) and I developed a 3 way switch for the switchpitch trans cars and it worked great. (Fully controlled by the micro switch and kickdown switch, high stall constant , low stall constant) all in 1 dash switch.

Full disclosure, I now have a fixed stall ST400 in the car but I really did like the ST300 with the 3 way switch.


Jerry

[elagache]

Dear Jerry and mid-60s Buick encyclopedias,

Full disclosure, I now have a fixed stall ST400 in the car but I really did like the ST300 with the 3 way switch.

Okay, I'll admit my ignorance.  I've never heard of an ST400 transmission.  Could somebody clue me in on what is this beast?

A curious mind wants to know!

Edouard 

[EZ Cool]

ST400 (Super Turbine 400) is the predecessor to the TH400. although it had 3 forward gears it was not possible to manually control the 1-2 gear change. I believe it was only produced for the 64 year model. The SP400 came out the next year and it had a switch pitch converter and the 1-2 shift was manually controllable. I often wondered why the SP400 wasn't available in the GS behind the 401 nailhead. I am building a 65 GS clone and it is going to have a SP400.

[elagache]

Dear EZ Cool and mid-60s Buick evolutionary biologists, . . . .

ST400 (Super Turbine 400) is the predecessor to the TH400. although it had 3 forward gears it was not possible to manually control the 1-2 gear change. I believe it was only produced for the 64 year model. The SP400 came out the next year and it had a switch pitch converter and the 1-2 shift was manually controllable. I often wondered why the SP400 wasn't available in the GS behind the 401 nailhead. I am building a 65 GS clone and it is going to have a SP400.

WOW!  I had no idea of this evolution of GM transmissions.  This actually makes much more sense with all these missing details.

THANKS!    That's what makes this forum da' real McCoy! . . . 

Cheers, Edouard 

[gs spoken here]

Does Transgo make a shift kit for a ST300?

[jmos4]

Hi,

Transgo doesn't make a "shift kit" this article is what I found searching online for tweeks to improve the performance of a st300.  I am sure if you gave the article to someone rebuilding a transmission that they could incorporate it.

Also I got my gaskets from Fatsco, and up until yesterday they were unaware thete was 2 different valve body gaskets, even though they had sent me both types, so I believe if you go for this modification get both types so your not left waiting for the correct one.

I have yet to get my car going to see what difference the hole size makes, will let you all know.

Regards,

[GS66]

Good luck! It will be interesting to hear your report.

[jmos4]

Hi all,

Finally got some miles on my project, mostly driveability issues.

Well the article modifications do help, much firmer shift, still no rocket ship, but much better than any ST300 I can remember.

Regards,