Depending on the individual stovebolter's project plans, the 230 and/or 250 engines are definitely a viable option. The 292 is taller, heavier, and uses more fuel than the others, but it's a torque monster the hotrodders love. The only competition a 292 has, performance-wise, is the Ford 300 cubic inch inline. All those GM inline engines share the same cylinder head and bellhousing bolt pattern, and most of the go fast techniques commonly in practice apply to all of them. One really nice thing is that the latest-generation inline sixes share the same bellhousing shape as the Mercruiser 4 cylinder, a lot of the GM V6's, and small and big block V8's. I've got a project in the pipeline involving an Excalibur fiberglass roadster that could be running "any of the above" engines on a particular day! It will most likely run a highly modified 230 with three side draft carburetors and a roller cam and a bottom end that will be capable of living comfortably at 6K+ RPM if necessary. I like "little engines wound up tight!"
The same sort of motor mount modifications needed to adapt a stovebolt to a small block V8 will work for a 3rd.-generation inline six. From there, the rest of the driveline fabrication procedures concerning installing transmissions, rear ends, front and rear suspension, brakes, etc. are the same as installing a "belly button" small block V8.
On a similar note, a lot of Model T's got retro-fitted with Model A powerplants and transmissions back in the 1930's, if a hotrodder didn't want to go with the flathead V8 conversion. There were overhead valve conversion cylinder heads available for the A and T 4 cylinder engines, too! "There's nothing new under the sun!"
Jerry
