I have a 74 98 that is in the shop once again

for both sides blowing out the exhaust manifold gaskets. I have replaced the thermostat to a mid-range (160 degree, I think) and replaced the fan clutch. Is there anything else that I should look for, replace, try, etc? I love my baby, she is in great shape (original paint and still looks good), but my pockets aren't that deep to keep taking her in every two or so years to get the exhaust manifold leaks fixed. Sometimes it is one side, while others it is both. The previous owner mentioned they "fixed" the problem about 12 times: I am on number eight. She likes to warp them and go through the exhaust manifolds if I let the problem go too long. She is just driven locally now and no long trips (over 1 hr) because she can over heat in the summer with the a/c on, and I am so paranoid about blowing the gaskets over and over. Will someone help me please?
