I just changed my thermostat,I put in a high flow 195 .I read that this is a tough job considering the placement of the bolts.
Here's the easy way........easier
-drain the rad
-remove the upper rad and bypass hoses
-mark position of the distributor
-loosen distributor mounting bolt
-turn counterclockwise as far as it will go
-bend an old 1/2 inch wrench..see..picture below
-use this to remove the short %&*#@ bolt by the distributor
-when replacing ..set the housing + gasket + thermostat to the intake manifold..
-start the 2 bolts
-pull the housing and gasket back
-use a small piece of wire and pull the thermostat up slightly
-push the bottom of the housing against the manifold
-release the wire gently and make sure the thermostat is seated properly
-tight the bolts
-return distributor to its original location
-tighten all hoses
-replace antifreeze
-start and check for leaks
If you want to replace the hex head bolts for allens,the short bolt is 1x5/16 NC18 and the long one is 1 1/2x5/16NC
Hope this helps .........

[size=1]I just changed my thermostat,I put in a high flow 195 .
...
Congratulations.
Why is there a Pennsylvania plate in your avitar next to a Canadaian location?
http://www.lscclub.org/cars/oldschool1/images/oldschool1011.jpg

John "I-Think-Too-Much" Dancy

I went out and bought a 1/2" offset ratchet wrench, just for this.

That is a beautiful tool for this job. :wrench