Don't know the torque specs, but I have a couple of hints: 1. They usually break when; A. You tighten one side completely before starting on the other, and/or.. B. The thermostat is not set properly in its indent in the housing. The housing are also made out of low grade metal, which breaks easily. If you use a stock replacement housing, place the thermostat in it's proper location in the housing, place some rtv on the stat (only a little) to hold it in place, and rtv the gasket to the housing. Let it dry before continuing. Then mount it to the intake, finger tighten both bolts, and tighten then in gradual increments until it feels snug enough. Make sure you tighten both both equally. If it leaks a little, snug it up until it doesn't leak anymore. Or, for $10, go out and buy a decent chrome replacement, that comes with an O-ring, and use that. They are made of a higher grade metal, and don't break as easily.
I've had bad luck with the chrome ones with the o-ring. I worked at autozone for a while and had several customers come back and complain that they leaked after a year...didn't believe it until mine did the same thing at almost exactly a year. Depends which one you get i guess...mine was the Spectre...it's all japcrap anyways.
I bought a chrome one from Mr Gasket. The first time at the track it spit the little crossover pipe out of the thermostat housing....its wasnt' even welded in, it was a press fit.....ruined a night at the track!!!! I threw the thing in the trash and bought a CSI housing.....
chrome ones with the o-ring...leaked after a year Guess I've been lucky, mine's been OK for about 3 years now.
as far as torque goes, i just tighten the housing as snug as i can using a thumb and 3 fingers on my wrench. i don't hold it in my hand. no leaks!
I had one of those Cal Custom chrome ones. Lasted over 20 years, tried to take it back but Woolworth went out of business. Dan I have always just made them snug, and if using a 3/8 ratchet with extension I just put the tightening force on the ratchet head itself, never on the bar of the ratchet. Has worked well for me.
