I've never heard a particularly good explanation of why, when the small-bore limited prep classifications were rolled out, there was such a major departure from the philosophy that was used to class the initial EP limited prep cars such as the 240Z (limitations on suspension, head prep, cam and compression only, but with alternate crank, rods, rockers etc. still allowed). When small bore limited prep was proposed, and was being worked on behind the scenes, I was under the impression that a similar approach was being used by the CB at the time, and was all for it. However, when small bore limited prep was rolled out as a bunch of "new classifications", surprise!, a new philosophy!, and a new de-facto rules set, with effectively no member input. By then there were dozens of new classifications in place, and it was too late to put the genie back in the bottle. In my opinion, the classification specs for cars like the 240Z are superior to those used for the small bore limited prep cars and later EP limited prep cars. The combination of performance limitation by airflow, together with robust mechanical components being allowed, gives what I consider to be an appropriate level of compromise between performance and reliability for club racing.