The head that came with my '50 1/2-ton is a 3835913. It's pretty beat up and I don't have a plan for it, except that I'm working on getting a 261 to drop into my truck and I've considered adding an 848 head for compression. If there's no difference other than my 913 and the later 848 except for the threaded temp gauge hole, should I consider rebuilding this head for my 261?