I've never heard of an "interim" shop manual before...........very interesting.

I hate to rely in hearsay evidence (it spawns "proof" like 409 wheels and '64 rocker panel moldings) but I had a guy tell me he tried to order a new 409 in January. The dealer took the order then informed him that it couldn't be filled until a new replacement engine was available. That story stuck in my head and I always thought neither big block was available for about a month. It seems odd that Chevy would discontinue one motor before it had a replacement. That's why it would be great to document the latest 409 and the earliest 396 known to exist. That kind of intrinsic evidence is the best and even trumps GMs printed material as far as I'm concerned.

Verne