New to Kaama's on a Formula 302 SR-1 1985. Are they reliable ?

Generally yes, very simple design, not too many moving parts, most seals, ujoints, and bearings are common, and easy to get at any bearing house. I usually tear mine apart every 2-3 years to inspect, change seals, and renew oil just as a precaution.
Why? Because the parts are hard to find if you can at all, so you don't want them to grenade for ANY reason. Haven't been produced since the early 1990s, so specialty stuff like the boots, shafts, gears, and castings are very hard to find, particularly in a rush! In that regard, I have two (2) complete drives (transmissions to prop nuts) that I've located over the years that sit in the shop as 'replacement' parts, although I've not needed even a single bolt. It's just the cost of running Kaamas.

I love mine! IN their day, they were 6-8 mph faster than Merc stuff, will have even the most seasoned boater wondering what the heck you have hanging off the back of the transom, and will kick a rooster tail 40' high and 120' long at WOT, but living with them is not for everyone. JMHO.