Thanks, guys.
I thought it was odd that bolts were so long (except for the two that the PO shortened with a hacksaw). It seems to me that you really need a control so I think I will install a cheap cable operated heater control valve like this:
(AC Delco #155814 about $23)
[img]http://www.rockauto.com/ref/ACDelco/15-5814.jpg[/img]


Gord
1954 1/2 ton 235 4 speed