Many old school guys really like the 186's more than the other double humps because they had the accessory holes in them(most other double humps do not). I mention this out of jealousy because I am running a set of (1965)heavily ported big valve 461 Feulies(nearly identical to your 186's) and now I am finding out the hard way what a pain in the butt it is to put a power steering pump in my car(she wants to drive it).
As far as performance potential goes don't expect them to run with a set of new CNC ported AFR heads, but they have more potential than most people give them credit for. (115mph in the 1/4 with a 3600lb car, no nitrous 383 on street tires full exhaust)

Have fun with them.