I bought and installed a B&M shift kit for a TH350 about 30 years back . I don't remember it costing very much either (I couldn't have afforded it back then otherwise).

Worked great and very easy to do. I'm less familiar with the Ford tranny's but shouldn't be a problem. Mine gave crisp shifts and I think it actually helped the tranny last longer ........

Godd luck, Kitz