[Don66GTO]

I have a 66 GTO with a 455 out of a 74 Lemans. It also has a TH400 with a either 8 or 9 inch tailshaft. the transmission went out so I ordered a beefed up one from the local parts store and after they got the right length transmission to me the output shaft was larger. I need to have the 32 spline yoke on my drive shaft. The old blown tranny used the 27 spline shaft I think. anyway has anyone heard of a th400 with 27 splines? the numbers for the tranny when run at the parts store came up as a 73 Lemans and a rolls royce.

I figured I could just get another yoke later so I started to finish installing the tranny when I noticed that the torq converter was not lining up with my flex plate. the holes on the new torq converter are farther away from the center. Has anyone have any idea how many different patterns there are for torq converters for Pontiacs?


Any help would be appreciated.

[rontiac]

First off, it sounds like your old trans was either a T350, or a T375. The T375 is a Turbo 400 with the smaller T350 output shaft, basically. There are 2 separate bolt patterns for the T350 and T400 converters. Some 70's Pontiac flex plates are drilled for both. The older flex plates are not. Hope this helps a little.

[Don66GTO]

The transmission must be a TH375 then. before getting a new tranny I changed out the filter and the pan seal with a kit I bought as a TH400 kit.

Does anyone know what size flex plate to get to go with the TH400 off the top of their head?

[engineer]

two patterns for convertor holes and two center hole diameters. only one overall flexplate diameter. At the auto store, buy the flexplate from an OEM supplier like Pioneer, will come with both convertor patterns and large center hole.