91 Celica GT. Any suggestions out there?

We don't have that year, but close.  check the wheel bearing, as all of ours were bad.  We had thermostat issues that had us almost overheating most of the event, and the coil failed, so bring a spare.  And according to the judges, all fwd celicas blow up, so bring beer for afterwards.  Good luck.

Ours is still alive and kicking.  Getting it prepped for a couple of events this year.  We got the thermostat changed, and are working on removing the ac stuff.  It actually did pretty well at Nelsons last year, was fast when you could run it hard, used no oil and generally had no issues other than the coil packing it in at about 7am sunday morning. 

During the event we couldn't change the thermostat, due to heavily corroded thermostat housing studs.  Didn't want to risk breaking them off in the block.  We just soft pedaled it mostly, and stopped about once an hour or so to refill it with water.  We ran it harder the last couple of hours, but the motor seems to be fine.

Some of the issue with overheating is the water pump cavitation at high rpms.
We run the 4age in our MR2 and have found that if the system is not fully bled and pressure tested, any small amount of air that gets to the water pump will cause it to stall. You will not have much warning about the overheating, the gauge will spike once or twice and drop back to normal and then all at once your hot and blowing fluid. The issue is Toyota's can run forever but not at 7000 rpm for 8 hours straight. To find out if your water pump is cavitating test the temp at the radiator it will be warm or cold.  The first thing to go on the engine will be the head gasket, always bring a spare.

Email me off line and I can give you a little more info if you want.

The first time you do it you'll think its the hardest thing you've ever done.  Then you will finish and realize it wasnt that bad.  It get's easier each time.  Get a manual so you have the proper torque specs and bolt pattern.

We put in a new head gasket at Buttonwillows on Saturday and finished out the day and the rest of the race. We had practice in the shop before the race on another engine so it wasn't so bad. The cool thing is that we left the intake and exhaust manifolds on and removed all of the pieces together. Put them back the same way so we ended up using only a head gasket. Done in a 4-age MR2 for those interested, and the same engine and gasket finished Thunderhill with no issues. I think that's what puts the thrill in the race. Having challenges and still finishing. There are a lot of other teams that have done 1, 2 and I think one team has even done 3 engine swaps in one race. Ask Tarp racing if it's worth doing on day two, they got the "heroic fix" award at Houston for traveling something like 8 or 10 hours to get a motor back to the track to find out it only ran on two cylinders. They got the engine in and running with something like an hour left in the race. JThw8 is right you will want the manual with you at all times. The cool thing about running into issues is that it's like having a Thousand MacGyvers at the track. there is always someone who knows how to fix it, usually with JB Weld.