The 250 and 292 are a different animal then the 235. That being said, the later motors share quite a bit of design and engineering attributes with the V8 chevy, are lighter, and frankly a more improved design with higher power/torque capabilities. Both the 250 and 292 use the same bellhouing bolt pattern as the V8 which is helpful in swapping them in. That and parts are easier to come by. But they are not a drop in swap by any means. So its a trade off, easier way is to rebuild or replace what you have with the same thing, and live with the lower power, or the more complicated is the later model 250 swap with the improved power..
