I have not done this before but I know I was the source of the install the transmission frame mount before the engine goes in. This was specifically talked about in the August build school and both Todd and Scott said to put it in first. The reason stated was it was much easier to access the bolts for the mount and get those tightened without having to work around the transmission. When we installed the engine at the school that trans frame mount was already in there and that 302 went in nice and smooth. It wasn't beat up either from the transmission hitting and scraping it.
I cant believe I am 2 weeks in with my kit and have the nerve to say something different than GoDadGo, what am I thinking

Now I am curious. What say those that have experience here, install the transmission frame mount before or after (per the manual)?
Ron