I've replaced plenty of t-stats, but never on a motor with a heat exchanger. How hard is it to remove the exchanger? I have a 496 manual that makes it sound very easy, 2 or 3 steps. I would think the process would be the same on a 525.

Any tips or tricks that make the job easier?

Drain coolant, remove hoses, loosen resivour bolts and slide to the side a little, loosen the two allen bolts on each side of exchanger, pull it off. May need to take air filter off also. On the allen bolts I used the straight allen wrench that has a socket end on it so I could put it on a ratchet. The end of the allen has like a round allen head on it so you can use it at an angle because the bolts are real close to the heat exchanger, may need to take off the shift linkage off header also. Not hard with the right tools.

Thanks! Jobs like this always seem to have a hidden suprise.