LameHoof65
Famous Member
I went to the classic mustang place here to see if they had the retainers for the 260. The guy said yes, and indeed they looked quite similar to the ones in the Handbook, but I was skeptical and questioned the salesperson a little and he took me over to his parts manual. Sure enough it listed the 289 retainers the same as the 260. I told him that I had a manual stating that the 289 valve stems were of a different size. He said he thought they would work, so I took them home. I tried a test fit without the spring, just to see if they would catch appropriately on the stem hole when I put pressure on the keepers from the bottom of the retainer, they slipped off every time. So I tried it with the valve keepers from my 250 head, they caught and held tight, but way to low in the hole, about a 16th of an inch to low. Also I have bought some clevite exhaust springs for a 79 351 Windsor. Okay, now for my question---what do I do? Keep the 79 351 exhaust valve springs and use my old 250 retainers and keepers, or try to find the appropriate 260 retainers and keepers or try to find larger keepers to take up the slack and will position the stems high enough the rocker won't be hitting on the retainer? I put my micrometer on top edge of both of them, the "so called" 260 retainer and it was approximately .085 thick while the old retainer was about .105 thick...I think this is a little thicker than the one in the handbook. Now the Clevite Springs were 2.041 tall (never having been compressed), while the old springs were about 1.811 tall. Again, need some input here---it has been awhile since I have read a micrometer--so maybe I am reading it wrong. When I say keepers I am talking about what some refer to as "valve retainer keys". 
One last note the overall thickness of the old retainer was approximately .105 thicker than the new retainer---I am thinking that the overall thickness is what you are refering to in you book,right??

One last note the overall thickness of the old retainer was approximately .105 thicker than the new retainer---I am thinking that the overall thickness is what you are refering to in you book,right??