Thinking about an overdrive? Who's done it? Suggestions?

I did a 200 4 R, works pretty good for me, am now installing a Hurst Pro Matic II, ratchet shift

The 200 4R is my next tranny.

I just did a 4L80E conversion. I was running a TH400 with a loose converter. The lock-up converter with the OD tranny is awesome. At 65 mph running 3.23 gears my rpms dropped from 3000 to 2000. That impressed me. It's pricey though, and you might be ok with a 200R4 but I just knew I would be one of those guys that killed the 200 in a short time so I went with the heavy duty route.

Am I wrong or do I remember someone saying the 4L80E is the same as a th400 only with an overdrive?

I'm no expert but I know they share some of the same internals. Also, the 4l80e applications are where you would normally see TH400's, ie: heavy vehicles with large displacement. So yeah, as I understand it's a true decendant.

Could I use the same convertor?

No, but while that's an expense its worth it because it will be a lock up converter. When the converter locks up while cruising it will drop the engine rpms down a little more. It's a slight bump, feels almost like a 5th gear.

Are there higher stall lock up convertors?

Absolutely! You can get whatever stall you want AND have it lock up on command.