There appears to be two styles of driveshafts used throughout the 64-66 production. The earlier HiPo's used the style with an outside snap ring.
[Blocked Image: https://lh4.googleusercontent.com/_FhFCoO_tIME/TWf6cj5S_AI/AAAAAAAAUfo/5uqZDTodV3Y/s640/IMG_0094.JPG]
In very late '65 production (?) (April-June '65 ???-at San Jose, at least), there appears to have been a change to an inside snap ring style like this:
[Blocked Image: https://lh5.googleusercontent.com/_FhFCoO_tIME/TWf6oWVMcmI/AAAAAAAAUfw/VCIADeJSuqU/s640/Internal%20clips%20U-Joint.JPG]
I am interested in hearing from owners here as to which one is in your particular car. Please provide approx. build date, plant, if you think it is original to your car, and casting number on front yoke if possible.
I'm particularly interested in that production time between around April '65 and June '65. Thanks.