Went to R&R the thermostat on my 86, 6.2 burb today. Noticed the housing was starting to leak. So decided a new thermostat was inorder also. The first odd thing was the bolts holding the housing on were 2 different sized heads. Top bolt took a 14mm socket and the botom took a 15mm socket. Doubled checked and no Amercian sockets fit. I know Chevy was into odd-ball mix match SAE and Metric bolts in the mid 80's vehicles, so this didn't seem too odd. Top bolt came out no problem. Botton bolt, as usual with every single thermo housing I've ever messed with, busted off Luckily some PB Blaster and large vise grip got it out. Never have I had a thermo housing bolt bust off and leave me a nub to grab onto. I'm buying a lotto ticket tonite since my new found luck. Ok the really odd part begins with my trip to the local auto parts store to get 2 new housing bolts. Always like to put new bolts when possible. Both of the old bolts have metric symbols on them, but only one bolt has metric threads. Top bolt is a 3/8-16 and bottom is a 10mm 1.50 Had the parts person baffled...lol Anybody else run into **** like this on their Chevy before?