I'd leave as is with a 350 eng personally. If you soup it up, maybe worth an upgrade, but if you're going to spend the $ on an upgrade, recommend a beefed up overdrive trans for lower highway rpm, unless you currently have a 3.07 in the back - in which case it may not really be necessary. For a driver that you aren't doing burnouts in (IF you aren't doing burnouts in it, that is
), a TH350 is a sound, reliable trans, not worth the effort to swap in my opinion. If you are doing burnouts, I'd still wait, if it fails, then that means it's time for a swap - so, maybe I should say it's not worth it to pre-emptively swap it as it may not be necessary.