yes Jim the parking gear somewhat registers on the ground portion of the shaft so i figured maintaining some of this fit would help the gear run true. as for the measurements it was really kind of an eyeball hack job but when i get things properly mocked up i'll try to get some accurate info. it may be splitting hairs but the thickness of the extension housing gasket as well as factory tolerances comes into play with regards to the location of things. as mentioned i can't say doing it this way is necessarily a good idea. one thing that concerns me it that keeping the factory dimension from the oil hole forward (which means it will still act as a bearing) could cause a problem with the needle bearing. if the bearing doesn't carry enough load it can cause the needles to skid as opposed to rolling which will eventually ruin the bearing.

John i had considered the points you mention and do agree, this is mostly just a "let's see what happens" type thing. for this car a stock rebuild with a valve body would be more than sufficient, it's really just tinkering around. i still haven't decided if i'm going to install the four needle thrust bearings in the back end. it seems to me to really do the thrust thing right you'd need (off the top of my head) eight bearings from front to back.

remember i don't have near the experience or knowledge of this transmission that you guys do this is one of only two or three of these i ever messed with and the others were thirty years ago.

There may not be an advantage to having a thrust bearing at every location, as some locations may only see intermittent bump loads or only be loaded in certain gears.

And remember that a bearing provides reduced friction but at the price of reduced wear surface area. And the more bearings you have, teh more critical endplay and stack clearances will be.