I think with a car like a ZL1, a lot has to do with timing...I suspect that certain cars without the original motor on a given day have sold for more than cars with the original motor...if you just gotta have a ZL1 NOOWWW...you have to pick one that is available now...with a Z28 or other more common RPO, there are always atleast a handful available at any given moment.With a Zl-1, your lucky if more than a couple go up for sale in any given year...I think that some cars sold in the recent past few years to collectors that just had to have one...lets face it, if you have a collection of the best Chevy musclecars and money is no object, your collection is not complete without a ZL-1...
And as far as Jim from Heartbeats car for 1.4 million, I'm sure the restoration is beautiful, but if I had 1.4 mil to buy a ZL1, I would solicit other owners of a more desirable color(and definitely a 4-speed) and I suspect you would have atleast a few owners willing to part with their cars for that kind of cash...1.4 mil sure would get my attention
just my .02