Was out in the garage getting things in order before the incoming snow and was in the area of where my spare TH 400 transmission. Thought I'd take a look at the tag and I was a bit surprised at the result. The tag is yellow with O B then below it was stamped 78-OB and some other numbers. Can this be built to be behind a Stage 2 headed motor and hold up? For years I thought it was my BB 71 transmission..The O W transmission is in my car currently.Is this worth the time or should I look into getting a different one??
I would fret about that tranny.......the only part inside you might want to look to change is the direct drum. The sprag is a roller type. Which is stronger than factory 16 element sprag......but the smooth earlier drums are a very easy upgrade to 32 element sprag. You can get the direct drum out of a 4l80e to do this too.......but that unit isn't able to be dual fed as well as the early th400 are. But that sprag, dual feed direct drum, good shift kit and some good high energy fractions and you will be good into low 10s high 9s very easy
Most likely(although it wasn't planned this way) I may just pull the OW transmission and have that rebuilt..I'll keep the 78 trans and use it as a spare if the need arises..Just wasn't sure the newer transmissions were are good as the 70-73's...
They are, the 400 didnt start getting really chincy till the mid to late 80s. And even the the gears and stuff wasn't the issue as much as it was the pistons and stuff they changed
I am at the point of transmission choices.I just may have the 78 transmission done as it's sitting in the corner of my garage now..Apparently,there is trouble locating all the necessary parts at the moment. I have been considering a rebuilt unit from Summit,but I don't know anyone who has had experience with them..
Too bad we were not closer I'm sure I have enough stuff ready to go to build a fresh 400. I dont know why parts to rebuild would be hard to get for these now, I looked kits uo the other day and there was no shortages
