I've seen this ad on C'List here for a couple months, (surprising)! https://baltimore.craigslist.org/pts/d/davidsonville-pontiac-olds-buick-turbo/7071978884.html
Oh look. Here is one . Found just that fast https://dayton.craigslist.org/pts/d/pontiac-th400-rebuilt/7093175888.html
https://buffalo.craigslist.org/pts/d/buffalo-1968-bop-th400-transmission/7103383926.html And another.........if I was closer to buffalo I would buy this
If I have the time,I would pull all of mine out for a picture and send to him,but I’m not wasting the effort. Maybe I should send a picture of my Reid-case TH400.
No they used them later too. They also have a thicker pan rail and a stiffing rib head towards the output shaft to go along the thicker bellhousing and extra webbing support in that area.
Should like like this I would assume with an aftermarket bellhousing https://www.jegs.com/i/Reid+Racing/...qGX8hq5VffPtHm7TA2_aIAx9q5D16WvBoCkDkQAvD_BwE
and another few more. https://sacramento.craigslist.org/pts/d/roseville-hughes-racing-th400/7109441854.html https://sacramento.craigslist.org/pts/d/bpo-buick-pontiac-olds-th400/7105261348.html
Thick or not,they still break like the rest. I broke one on the dyno. From the pan rail up an over to the other side. Broke another one on the inside.
Appearing in the late 60's the "HD BOP case" TH 400's were first used in full size car builds. Most were long tails, but there were some short tail transmissions out there. This case resists bellhousing cracking very well, but the case is otherwise unchanged from the standard "thin bellhousing" cases. If available, I try and use one in all my Level 2 builds. Interestingly enough, the HP units out there in the GM muscle cars, all had the think bellhousing. It was more of a weight thing, than a power thing, with the factory builds. JW