A buddy and myself, have been going back and forth on which is the better option. Price, parts availability, maintenance. I had been leaning towards the 4l80e, but the th400 is looking pretty good too. I'm still piecing together my dragweek car. An overdrive is a must. Not a real heavy car, 3000 lbs plus driver. Small tire and in the neighborhood of 1000 hp na. Which way do y'all recommend?

The TH400 + GV cannot have a locking torque converter, 4L80E can (but $$$ if you need WOT locked).
Both require D/S mods; shorter makes the angle worse but the D/S will be stronger.
4L80E may need tunnel bashing due to large diameter far back?
Both require serious aftermarket parts for your power level.
GV adds more length, make a worse D/S angle.
4L80E controls are more expensive but useful.
4L80E has slightly taller O/D at .75:1, GV is .78:1, otherwise the ratios match.
GV is far more expensive (than the extra cost of 4L80E over TH400).
See my table of O/D transmissions here:
http://victorylibrary.com/mopar/aod.htm

Did you know there is a 6L80E...?

Just to throw in my 2 cents, the torque converter availability for the 4L80 is not as good as a 400 but with the right manufacture they are out there. The 6L80E is a valve body modification to the 4L80E and some preliminary reviews I read seem to be a little less than impressed. Tunnel modifications to a Mopar to make them both work may be very extensive. Depending on power level I would seek out a highly modified TH200R4 and know there is a vendor that makes an adapter. Converter choices are good as well.
Edit, just reread the OP and see the power goal is 1000HP and may be a stretch for a modified TH200R4.
AG.

I have access to a gv that is much cheaper than the list price of 2700. I like that the 400 has fitted shields available, not a blanket like the 80 would have to use. How much is the lock up in the 80 worth?

With 1000 HP I don't think I would bother with a lock-up style converter. The lock-up cores limit your optimum selection.
AG.

TH400 is the drag race tranmission. Can easily hold 1000 HP with minimal extras.

I used an Extreme Automatics Stage 2, 200R4 with lock-up in my '68 A-Body. That version of the trans is rated at 700 hp, but my motor is only putting out 500 hp. The gear ratios are nearly perfect, and the lock-up is like having a 5 speed, as I run a 3200 rpm stall converter from Precision of New Hampton. The lock-up clutch uses a HD 3 carbon fiber disc clutch system that was designed for modified diesel pick-ups.

For the 1000 hp power level, you would have to look into their Stage 3 version. It is rated for over 1000 hp. It makes for a clean install too, especially if you use their adapter and a Reid bellhousing. US Cartool now is making a crossmember adapting kit. I had to modify the torsion bar crossmember, but not the floor.

I'm running a coil over front end, so no torsion bars to contend with. I can remove the mounts and make more room in the tunnel, that's not as big a concern. I looked at the 200 as well. I don't think that I need the low first gear. Actually if it weren't so much more I think that I could use the 210 first and be ok. What about a glide with a gv? To much converter slippage?

A higher first gear ratio, gear set is an option from Extreme. It is similar to a 727 first gear ratio.

If you want the motor up near stock height your going to have to put a tunnel in the car. I have a TH400 in my 69 Dart and I had to drop the motor a lot, that's with the torsion bar cross member and the trans cross member cut out.

I spoke with Lonnie at ea. He told me that at my power level he would recommend the 80. I would be on the topside of the 200, but have room to move up with the 80.