Carl, Thank you for the very interesting info and thank you for the link to Zhome.com! I will register our '71 amd '72 240Zs in the next couple days. I noticed that you have #20, that's terrific!!! I saw that #390 (needs restoration) is currently on eBay, item #2479358623. I also noticed that you have a '72, white with red interior, that's what our '72 is also (#64733, with the engine matching the data plate #081097). My son and I have had a real tough time finding the red interior parts during our restoration process. With regard to my original post on the extra engine we have with the E31 engine block, E31 head, E88 intake manifold, Hitachi SU carbs, '70 air cleaner, Series 1 valve cover, and the higher #060039 engine number I am still at a loss, everything points to a '70 engine with the single exception of the high engine number. You hve come up with some very good ideas on why this is, but your'e right, it is a strange specimen. Thanks again and look into #390 on eBay, the seller says that if is not sold, it will be parted out and "sent to the shredder". That would be a shame for one of the rare "500" 240Zs to end up like that.. Maybe one of the classic zcar members may look into saving this historical car!!