Hey there, finally another classic Nova owner!!
I have a 66 Nova with the 194, and 2 speed powerglide.
Currently rebuilding the 194, installing a performance cam, and I added an HEI distributor from a later Nova with a 250-6.
I thought about an engine swap, but my car is all stock like yours and I want to maintain the original look and feel. Plus it's cheaper on gas. Email some pics if you can, I'd like to take a look at your Nova.