Sounds like the best MYs then to go with are the '87-'89s, that had the NON all-aluminum engine that the Allantes went with in '90 until '93 (with the Northstar being installed in '93s). Not that there was anything wrong with the all-aluminum one, but the earlier version was composed of good ole heavy-duty steel/iron/etc.

btw, I ran across this YouTube video today of "Chris Fix" successfully using a pour-in product to seal the blown head gasket on an (X-type ?). It held up for two years/10K miles of driving, before the gasket started leaking again. I was especially impressed by the fact that, after the leak reoccured he did a tear down on the radiator to make sure the product did NOT clog any of the water passages in same. I guess I'll give this product a try. It begins working after only a few minutes of the engine running, vs. 50 minutes for the Blue Devil product to work.

 

It's the heater core I always worry about with those products. The coolant passages are often much smaller than those in the radiator, and therefore more easily clogged. Personally, I would rather replace a head gasket than a heater core, even if you use the "cut the pipes" method. The dash and steering column must come out, and you have lots of age-embrittled, easily-broken and hard-to-source interior parts to deal with.

We will be very interested in your results!

Cheers,

Don