Hey JackD,
As long as we're asking what if's here, here's one I sent to another forum a little bit ago.
Let's say I entered a true dual engined liner (2 fire systems, throttle springs, etc.) with both motors hooked up end to end through their crankshafts and then out through a tranny and differential. Then let's say I left off the cylinder head(s) off of the front motor. Could I still use it to "upgrade" to the next class? What if I left off the intake manifold? What if I left off just the carburetor? Or maybe only the fuel line? What if I put a clutch between the motors so I could disengage the front one after the start? Ain't no specific rule about none of that. But at some point wouldn't you say "Bulls..t! That violates the SPIRIT of the rules!" and toss me out of the meet for being just too darn "cute" (or merely disrespectful of what we all are trying to produce here)? And yet as we all know, there is/are no specific rule(s) prohibiting that behavior. It merely falls to a preponderance of evidence argument or how insulted you might feel, rather than black and white fact.
Motors are composed of hundreds of parts. Miss a bit of key stock between the crankshaft and the cam drive gear and your motor don't go just as much as it don't go if you left off a cylinder head. It seems to me that a certain portion of the argument here is based upon the physical size of the "infraction" when, in reality as to whether your motor runs or not, size does not matter.
Okay, gotta duck back behind the sandbags.
(And FWIW I do NOT "sandbag")