Answering a few different things here.

1. Most of my experience comes from being in the new car business with Dodge from 1968-1974. I have had several old Plymouths over the years but basically rely on the factory info I have or have access to Which the majority is Dodge. I have nothing on Plymouth and know little about the minuet differences other than there were some from the two sister brands. This is apparently one of them with the availability of 440-4 speed-A/C. For Dodge they are specific to mention what the two 440s were available in and with what trans as well as very specific about what engine/trans combos A/C was NOT available with in this Data Book link.
http://www.hamtramck-historical.com/imag..._Monaco0020.jpg


2. As I stated previously in this thread my info on the availability of A/C with a 4 speed on a 375 h.p. car came from both the factory sales and service reps. I believe the concern was the very likely possibility of over-reving the engine and compressor with the manual trans as in missed shifts, etc. which is certainly not as apt to happen with an auto trans.

3. Thanks for the info on the h.p. ratings. Did that info come from pages 96/97 of the Data Book as I just noticed that page is missing from my book? I was not aware that the dual exhaust cars were rated at 365 h.p. and was only aware of the 350 h.p. rating of the single exhaust cars. The info above states the engine (s?) have a standard cam. Assuming they have the same cam and the exhaust is the only difference then why are they rated at different RPMs? Also, did the dual exhaust cars have hipo exhaust manifolds like the later 67 375 h.p. engines?