You can fit a later alum intake on your 65 heads. I have one on my 65 273 now. I had to "V" the bolt holes w/ a counter-sink bit and use flat-head bolts, but it works and doesn't leak.
You can still find the Edelbrock aluminum 4 bbl intakes for the 64-65 273 heads. I bought one for ~$100 the last year on ebay, just because I saw it and figured that was cheap. It is good that people are rushing to the 318 & 360 engines. That frees up these 273 parts for us bottom-feeders. Same way I got 2 sets of SBP wheels. I love when everyone changes to BBP. I just wish more would decide their K-H disk brakes should be junked.
My eventual plan is to put a Magnum intake on my engine (for cheap EFI), and yes I know the bolt angles are different, but am an engineer so don't fear minor things like that.