If this is just the stock AODE, shifting manually through the gears is not recommended unless you want to trailer the car permanently. The 4r70W from the mod cars can be manually shifted all day long. AODE, not so much. Naturally, it CAN be done, but youre putting the tranny on borrowed time. In our trannies, I think youd be better off letting it shift automatically. Manual shifting puts a lot of stress on the tranny and a lot of heat. The manual 1 and 2 are there for starting in crappy conditions, not for performance unfortunately. Im a certified Ford tech and trust me, at 160K an AODE is pretty much just asking for an excuse to leave you stranded. If you want to keep an auto tranny, you can use your case and swap it out for 4r70W internals with minor mods. Or swap to a T5, thats what Im doing. As for anything being worth it, it really depends oon the car. Is it in good shape? Because mileage doesnt necessarily mean anything, Ive taken several 5.0s well into the 200K plus miles with absolutely no problems at all but I have access to all the necessary tools and a lift to do all the regular maintenance myself. My 88 LX 5.0 had 220K miles on it and would still run a 13.9 at NED before I sold it. The 5.0 is a very durable engine. There was an article on the net about some lady that has a 89 GT with over 750K miles on it and still going and the engines never been apart in any way. The biggest thing in my opinion is the body. If its starting to rot away or something, then it probably wouldnt be worth it to put too much work into it. If not, then theres no reason not to. Just my .02