[ponyakr]

"...The strongest unbreakable trans Pontiac used was their 3 speed..."

Back in the old days, many of the quickest drag Pontiacs used a 3-speed instead of a 4-speed.

This site says that before the Ford top loader came along, the '56-'57 BOP 3-speed was the strongest 3-speed available. It shows that the Ford 3-speed showed up in Pontiacs in '64. I have no idea if this info is correct or not.

http://www.teufert.net/trans/man-hist.htm

This GTO book says the 3-speed top loader was used in '65 thru '69 GTO's. Also says that the '70 models no longer used the top loader.

https://books.google.com/books?id=O8cPeCzimXIC&pg=PA89&lpg=PA89&dq=history+of+the+3-speed+toploader+transmission&source=bl&ots=FvOaBnPkN7&sig=Per2ttOao4GP3gIIN_NxQoJdRss&hl=en&sa=X&ved=0ahUKEwjA06uXk7TSAhVMlVQKHaxwAKY4FBDoAQhOMAg#v=onepage&q=history%20of%20the%203-speed%20toploader%20transmission&f=false

And some other sites indicate that they were probably used in 442's & the Buick Musclecar models. And I would assume they were also used in the '67-'69 400 Birds, and probably the big GM cars also. Besides having the cover on top, instead of the side, it is said that these had FOMOCO on the side of the case.

This Ebay ad shows a '65 GTO top loader. They had a GM input shaft, and required a bell housing with the correct mounting holes. These bell housings were dual pattern, so you could also use 'em with a GM pattern trans.

http://www.ebay.com/itm/Dearborn-GTO-3-speed-/272563621340?_trksid=p2141725.m3641.l6368

http://www.4speedconversions.com/581.html