Better Tranny

[jocko]

You can easily beef up the TH350 for a mild small block, if you feel the need. But, stock is probably fine. In your case, TH400 too much of a headache. If you don't mind extra work or paying for extra work - get a 2004R. Overdrive at approx. same length as TH350 (no driveline mods, just some trans tailshaft mount re-wickering). Your mechanic probably has a TH400 ready to go, perhaps that is why he's pushing for it. If he thinks it's the same amount of work to put in as the current TH350, I'd find another mechanic, then the transmission.