Choosing a Moyer Thermostat Kit

[rickrose]

My question concerns choosing among the different thermostat options available in the online catalog. My 1972 Ericson 29 has a late-model A4 with the thermostat mounted on top of the cylinder head. I like the idea of installing a spacer so that I can use the aftermarket thermostat. Several of the kits involve using the existing thermostat housing studs. To do so, the thermostat housing must either be modified or replaced. Another kit supplies some longer studs. However, the verbiage suggests that replacing those studs may somehow be more laborious than modifying the housing. You even mention removing the head!

My question (whew!): What makes changing those studs so difficult? Are they attached some way on the inside surface of the head? Otherwise, I would think I'd just use a locknut on each along with some PB Blaster and heat.

[Don Moyer]

They're regular studs except that they (like the lifting eye studs) have an extra couple of threads on the lower end. This extra length, plus the fact that they have frequently taken a bit of water into their annular space when removing the thermostat housing, makes them a bit more problematic than the other head studs.

Don