69 thermostat bolts?

[dick foehringer]

what are the bolts and heads supposed to look like on a 69 427/400? some cataloges say aluminum had studs others say bolts. it has the correct 660 aluminum housing and had two bolts that had 3 lines on them. i am also looking for a nice 660 housing. mine is pretty corroded around the hose area.
thanks!!
regards dick

[Joe L.]

Re: 69 thermostat bolts?

Dick----

The bolts you have sound correct. Both bolts should be 3 line (i.e. SAE grade 5 or GM 280-M) and be standard, trimmed (i.e. NOT indented head) hex head bolts with no washers underneath the head. Some common headmarks are "C" or "M", but there are likely many others that were used, too.

The thermostat housing you require is reproduced for about 40 bucks per copy and the reproduction is accurate in my opinion. Otherwise, go to a self-service salvage yard. This particular housing was used on MANY other Chevrolet engines of the late 60s to about 1973. They're quite easy to find. Of course, many might be suffering from the same problems as the one you have, but you can find excellent ones, too. I once found about 5 near-perfect examples on a quick trip through a self-serve wrecking yard.