I was working on my car this weekend and I have the tranny out and I noticed the bellhousing had some letters cast into it. It said " M7". I`ve never noticed these before on my other th350 trannys. My buddy who is a gm tranny guy said to look for a few things and that it might be a th250 and not a 350. I won`t be able to check anythign untill next weekend since the car is a hour away but I thought I would check with you guys. Thanks.