Moose, I think ur in good position. It was all together all ready in the mustang so it should all work together for u in the ranger. For the c4, they had a few variations along the way. From all the research i did, the smaller 157 tooth bellhousing gives the most clearance and is the desired one for our tight fitting trucks. U might be in good shape there being ur combo. There should be a tag on the side of the trans with its build code. Here's a great resource for c4 trans:
http://www.pigseye.com/sadie/trans/c4.htm
getting some more out of the engine, the carb will def help..Letting it breath well exhaust wise will help max it out with out going over budget here since u said ur going with some flows. Header clearance may be an issue but I've read that some of the older stock 302 manifolds worked. If they don't, grab some patriot long tubes:
These so far have cleared everywhere for my build. If u have the 157 th bell housing then they "should " work for u.