If you have the $$ to go 904
and cams, that would rock. If you have to choose between the 904
or cams, i would definitely go with cams first. The torque difference between the 865 and 904 with stock 865 cams is negligible.
I have run stock 865 cams in my 904 for a short time and was very disappointed in the results. The British customs stage 1 street cams i had made a huge difference.
I have since retired my old 904 and parted it out. Now i have a bone stock 865 and the torque is comparable to the 904 with 865 cams. No real seat of the pants difference. My next big purchase will definitely be hot cams. No question about that decision based on my experience. The 865 cams run out of steam way too soon. After the cams will be a Procom CDI.

...and i knew there was something wrong with that T-Bird price. LOL!