From what I have read the T50 is OK on a standard or slightly modified motor. I was also going to use a RWD motor to make it easier.

My T50 was behind a slightly worked engine and copped a lot of abuse for a couple of years until I sold the car with absolutely no issues

If you want to go 4age go for it it's your car, post some pics of the fitout...........
The zetec may be a bit more expensive to initially convert, especially if you want that oh so horny cam cover (not that expensive really) however the engines themselves are, and, will be a dime a dozen in the future, I saw a whole mondeo with rear damage go for $400 at auction. Not to sure about the 4age but the front cut of other japper's like the fj20 seems to have dried up now.....
Good luck with it Drew............

Ive got nothing against with other manufacturer engines in escorts (I'm putting in an F20C in mine after all!!). And the 4age has always been a pretty solid performer. I just think the extra capacity of the Zetec, and if done properly is something escort enthusiasts would be more willing to go for.

Maybe you should have bought that rocker cover? You might have made an extra $2500 haha

phoenix 13918
My T50 was behind a slightly worked engine and copped a lot of abuse for a couple of years until I sold the car with absolutely no issues

Yeah sorry, my memory is failing.  The boxes I was referring to are the C50 and C52, which are used in transverse applications.