Attached 1967 TSB discusses the problem of rocker arm studs pulling out of the head, and the solution. Interesting factoid that the factory (Winters foundry ?) started installing helicoils in all aluminum heads (ie. the first design cast 3904392's) as of May 22nd 1967, and I assume on all aluminum heads thereafter (ie. the 3919842s and the 3946074s).
P&A30 parts catalogs history shows the first design stud (ie. for '65-66) was #3860006.. Then for a short period of time (5-67 to 6-67) service was to use #3904395; after that the stud # was (and still is) #3921912. The stud for aluminum heads (longer thread, per Roger Gibson article in Restorer of Summer 1991) was # 3904396, per info circled in green in 2nd pic), and I'm guessing, was installed in the early aluminum heads. Anyway, this # was replaced in service, by the same 3921912 in 11-68. Don't know why this would have been so late if there was a problem with the aluminum heads 18 months before that .
The stud shown in the 2nd pic is from a set of oval port cast iron heads # 3917215, dated B-18-8, and I have no reason to doubt that it is period-correct, and therefore is # 3921912; 2.0" overall length. Anybody got a pic of the earlier part #s ?
Couldn't resist posting the 3rd pic of the outside temperature this morning, here, in Calgary Alberta. That's minus 29.5 C (or minus 21 F) Wind chill brings it close to minus 40, in either temperature scale.
P&A30 parts catalogs history shows the first design stud (ie. for '65-66) was #3860006.. Then for a short period of time (5-67 to 6-67) service was to use #3904395; after that the stud # was (and still is) #3921912. The stud for aluminum heads (longer thread, per Roger Gibson article in Restorer of Summer 1991) was # 3904396, per info circled in green in 2nd pic), and I'm guessing, was installed in the early aluminum heads. Anyway, this # was replaced in service, by the same 3921912 in 11-68. Don't know why this would have been so late if there was a problem with the aluminum heads 18 months before that .
The stud shown in the 2nd pic is from a set of oval port cast iron heads # 3917215, dated B-18-8, and I have no reason to doubt that it is period-correct, and therefore is # 3921912; 2.0" overall length. Anybody got a pic of the earlier part #s ?
Couldn't resist posting the 3rd pic of the outside temperature this morning, here, in Calgary Alberta. That's minus 29.5 C (or minus 21 F) Wind chill brings it close to minus 40, in either temperature scale.
. Took the thermometer shot through the kitchen window.
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