The standard temp sensor for that engine has a 1/2" NPT thread and fits in a tapered-thread hole between the #1 and #3 spark plugs on the driver's side cylinder head. If the heads you're running don't have that port, get a thermostat housing with a pipe thread in it and install the sensor there. The later-model thermo housings also have a 1/2" NPT hole which can be adapted down to a 5/8" thread if necessary.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!