Just an observation......this head has undergone 61 oil changes in its life, all at 5000 mile intervals.
Oils used are supertech, mobile 1, pennzoil, chevron, shell rotella, kirkland, and all the other brand name oils, all in the 15-50, 20-40 range and synthetic or dino, what ever was available. The filter was changed every 5K and used most any brand including fram, supertech, and even a marine filter pronto p04610. Valves have been checked for clearance at 100K with no adjustments and not been touched in the last 206. On this head I didnt check the clearances with a guage but by finger wiggle they are OK. So what is the point of all this......change the oil and filter every 5K and ride it like you own it.....
The discolored head in the bottom of the pic is a possible don'er head that is supposed to have only 12K miles on it.....we'll see.
Oh, the reason for replacing this head is noted in my post of "How to break a timing belt"
https://i.postimg.cc/pTTcXL7Y/image000001-1.jpg
