'66 Thermostat

[R N.]

I want to confirm the correct thermostat for my '66 427/425. From all the reference material I've checked it appears it should be a 180 degree. Can someone please confirm this for me. As usual, thank you for your help.

[Joe L.]

Re: '66 Thermostat

Kurt-----

Yes, it should be 180 degree. For 1966, all Corvettes used a 180 degree thermostat EXCEPT those equipped with K-19. California-delivered cars with K-19 were originally equipped with a 195 degree thermostat. However, for 1966 there were 3 Chevrolet engines which, when installed in California-delivered Chevrolets, were exempt from the K-19 requirement. These were the L-72 425 hp 427 cid engine installed in Corvettes and full size Chevrolets, the L-78 375hp 396 installed in Chevelles, and the L-4 engine installed in some Chevy II's.

So, whether your L-72 was originally delivered in California, or not, it was NOT equipped with K-19 and WAS equipped with a 180 degree thermostat.

[John Lokay]

Re: '66 Thermostat

Joe, In my 1966 L 72 engine I have installed a Robert Shaw 160 degree thermostat. Do you see any downside with this and should I bother switching to a 180 degree one? Thanks

[Joe L.]

Re: '66 Thermostat

John-----

I think that the 160 will be ok. Since a thermostat only controls the minimum temperature that an engine will operate at and since your overall cooling system will have a difficult time maintaining a steady state much below 180 degrees anyway, it really shouldn't have much practical effect, anyway.