Article by Jimmy Williams as published in The Inside Track, Carolinas GSCA chapter
On the way home from Bowling Green, I was passed on the highway by a group of Grand Nationals and a number of Street Rods. I wondered what it would take to put an overdrive transmission in my 1972 GS. First of all, would it hold up to the torque and would it last if I drag raced it on occasion? Second, would one bolt up to my Buick bolt pattern? At that point, I did not have the slightest idea if it would work. However, I knew if it was possible, I would do it.
Several weeks passed and the idea of an overdrive trans faded. Then I received my copy of the big block tech session from the Nationals. The very first question was whether a 200-4R would hold up to the power and torque of a built Buick 455? Art Carr was there and answered in-depth about how his trans would hold up. I called Art Carr, 714-962-6655, and asked him about my application. I finally ordered one of his 200-4Rs.
There is no exact kit that works for the Buick 455. There were a few tricky pieces and some exact specs to adhere to as follows:
The great thing about the 200-4R is the first and second gears are a little steeper than a TH400. Third gear is the same but overdrive is 0.67! Since I have a 3.42 rear, overdrive computes to 2.29 on the highway. The car is much quieter and gets better mpg. First gear for a 200-4R is 2.74 vs 2.48 for the TH400. Second gear is 1.57 vs 1.48.
If you have questions, please call Jimmy at 803-799-5016 WK or 803-783-7659 HM.