I think you're pretty much right on. I think a lot of people have a mental reservation about "hot rods" being a V8 muscle, and no matter what, 4bangers are tuners. In my opinion, its probably because no one souped up 4bangers back in the 70's. Well, comparatively speaking.
That, and I think that the real hot rodders, the ones that even know what an ls9 or a turbo350 is, know what a port and polish is, know how to adjust gearing, and have done all of that stuff don't want to be associated with the "tuner" crowd, who generally think a turbo 350 is a nissan. You know, the type that finish their can of Foldgers off and then weld it to their exhaust.
And to be honest, I can't really see a 4banger being a hot rod. Unless it has ITB's and no hood with a supercharger or something... To me, a hot rod is a 69 camaro with a roots blower and stupid big cowl induction hood lol. I'd like to see what other people have to say on the topic too, its an interesting observation.
ROTM June '13, PNW Crew #42, SR #245, Rally Rev #02