Which K member is better?
I can certainly see where you may have a point, as through time factories usually try to cut costs. But, likewise, they usually improved things as well.
I am no expert on k members, so I honestly don't know for sure. I said the spool mount version is better, simply because the mounting system is failsafe with a through bolt through the mounts, so they cannot fail completely like the biscuit mounts can.
I would appreciate you expounding on your assertion that the early k member is superior. I always want to learn, so please, can you tell me and the others here exactly why you say that?
Actually they are NOT failsafe. Unless you mean the mount won't seperate into two pieces. But you can be sure the junky assed later style DO fail. I have a set in my shop that failed. A motor mount failure is just that. Don't matter if it seperates into two pieces or lets the motor sag and shift in the mounts, it is still FAILED.
The 73 and later K members are know "breakers". If I sat down and counted, I would guess I have welded/repaired between 45-50 K members, all of them spool mounts. In fact, I had to reair my own 73 spool mount this winter. If I was charging a custmer the repair would have billed out at 7.5 hours. Here, where I live, that is $85.00/hr or $637.50. Plus, it is impossible to get solid mounts for the spool type mount. I was looking into making some from aluminum with a steel sleeve, but from what feedback I have had, no one would buy them.
The spool type mount was to speed up production time. Hell, I could argue (I can't really because I don't road race) that the road race guys claim the earlier K members drive better.
One more time....the spool type mount was used because it simplified assembly and sped up production at the plant.
They are more prone to breakage, less rigid and are harder to get solid mounts for (impossible).
But those who would argue with a sign post will continue to do so, either from lack of experience, ignorance or both.
Use what you want. FWIW...the 64-66 K members were different where the mount and frame meet. They changed the angle in 67 (IIRC they flattened out the 67-72). Was it a performance issue? Not at all. It was driven by production rates. That is all. Same thing for the change made in 73. Obviously, the factory didn't want to tell everyone that the reason for changing a good system was purely financial so they added the "fail safe" detail.
There is no such thing as fail safe. Ever.