Thanks for the info. Yes, I don't drive it much. I bought it new in 1988 and only have 118,000kms on it. It's never been in the snow and has only seen rain 5 or 6 times. It's been really pampered which is why it's all the more frustrating to have to deal with these type of issues.
BTW... the car was almost 2 years past warranty when the first HG failed and Toyota covered it under "goodwill".

Thanks again.

BHG
head torque is one issue with the inline six of that era but another major flaw is the bolt design
there are only 4 bolts around each cylinder and if you look at most other engines you'll see 5 bolts around the cylinder .
less bolts means more distance between bolts and less ability to keep pressure constant between the bolts
bolts should be replaced with studs
just replacing the head gasket with a metal one is not gonna cure the problem you need to surface the head and block to finer than even a machine can smooth it out
have a look at some of my bhg shots
http://www.ddmcse.com/turbo/bhg_2003.htm

the same engine in the same year 4 runner has been factory recalled but they didn't do this for the supra