A couple of things, Glenn:
1. You know the thermostat rated temperature doesn't mean that's the max temp your engine will run, yes? It just means it won't run any cooler than that. I'm certain you already know this, but sometimes it is overlooked.

2. Please avoid using a thermostat sold under the name Fail-Safe. It is sold by a company named Moto-Rad and the problem is there is a little ratchet device built into it so that if your motor overheats it will set up a Rube Goldberg reaction and will lock in the open position...and the thing will stay open forever if you don't remove it and fix it. I've seen them stick open at a mere 10 degrees past the rated temp value. What you have to do is take it out and use a pair of needle nosed pliers to get in there and carefully disable the ratchet part you paid extra for. I've had two of them and they both stuck wide open and the same thing happened to a friend a couple of years ago.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end