doc -
I've been running a 235 thermostat housing and thermostat on my 261 for about 12 years. I thought the 261 housing took a larger hose, but you are probably right about it being the same size - it almost has to be to since all of the radiator necks were the same size.
I sure would like to see a picture - if any body has one - of that thermostat. I probably should be running that on my 261 for things to be totally right. Anybody got a picture from a box or have an old one you can take a shot of?
Thanks for the help and oldblu49, I didn't mean to hi-jack your post. It just got too interesting for me to pass up!!

Hope it was OK! I'll shut up now!
Joe
