Major differences. 194-292 series engines were the last of the famous old Chevy sixes and ran from 1963' till the end of production in the early seventies. It is shorter, lighter and smaller overall in size. They looked somewhat the same to the untrained eye but quick inspection will spot the new engines immediately. Four screw valve covers, two piece push rod covers, distributors in the front and not in the middle, different distributors, and they used the V8 bellhousing so trannies would interchange. Internally they had larger bores and shorter strokes, better lubrication and improved head design but still an old Chevy style. I don't think any of the parts will interchange from a 235 to a 194, 230 or 250. Others will provide detailed info if you feel you want it. If I were you and didn't know I'd take a couple of measurements of what you now have and do some checking before purchasing.
