74 cis piston ring question
 

I posted this in rebuild forum, but figured I would try it here..
I was planning on assembling my pistons and cylinders this weekend but have run into a problem. I purchased Goetze rings for my 1974 CIS 2.7 from a very helpful fellow pelcan. I was checking all of my clearances etc when I noticed that the two compression rings in each set measured the same thickness. In waynes book in the appendix it shows the middle ring as being thicker than the other compression ring on a 74. Did I buy rings for a different type of injection or what? The middle ring would have way too much play if I used this set. The ring lands are all in spec and the old ring measures much thicker than the replacement one but also falls right into spec for what the appendix specifies. Any help woud be appreciated.

My parts manual shows 2 different part numbers for the 10/12 different piston cylinder combinations.
911 103 939 00 for Mahle Nikasil
911 103 956 00 for (LS),

Thanks Doug,

I have now located the proper Usa rings and they will be here Tuesday. Let this be a testimant to the importance of a diy guy Having Waynes book handy durring a 911 engine rebuild. This would have turned messy real quick. Thanks Wayne!!! : )