I'll bite... I'll go for option 2 - Final answer
Sorry for the trick question, but the answer is NIETHER. Get out of the Cash Cab and start walking.
I do admire your bravery.
Now for the back story.
I scored a "D4" bell last year, put it on a shelf and thought no more of it now that I "had one." Earlier last year, Ultimate Pinto and I gutted a 73 Wagon; he took the engine, I took the tranny. A few days ago I decided to clean the bell from the 73 because I had a "D4" and I was going to sell this "D1". As I clean it I discover it is a "D4". Now I know for a fact this came off a 2.0, so I attempted to install it on one of my spare 2.3s only to find it won't fit due to the dowel size. Then I grabbed my other "D4", and sure enough, it won't fit either. I started looking into this to find there are at least 2, maybe more "D4" bells, of which at least one will not fit a 2.3. The D4s have prefixes of “D42P”, “D4ZP”, and MAYBE a "D42F" and a “D4ZZ” (I have not been able to verifiy these); the “D42P” WILL NOT FIT A 2.3. This is something to look for when buying a “D4” bell. The dowel holes for a 2.0 are .480”, the ones for a 2.3 are .6”. All these bell part numbers will have the same middle number of “7976” and should also have some variation of “A”, “AA”, or “AB”, possibly followed by a dash and one or two more numbers (one of mine has a “-1” the other a “-2).
I hope this helps.
Bill