I'm not sure what its like on those OHC heads, but on my Fiero I overheated it maybe 5-6 times last fall (1-2 times really bad...) and it was just the waterpump. That cost me $30 to fix ($30 for the pump, and my sweat, haha). Its still going strong even now, and that V6 has about 150,000 miles and some overheating on it. You might consider just changing the pump first. If you think its the gasket, go get a compression check.