WOW! - that is a loaded question...I'll just give you a start since I can't write a full explanation at work and I'm sure there will be others that will pitch in. In 1969 Chevrolet offered the COPO Camaro with a 427 in two COPO numbers. COPO 9560 (ZL1 427/430) came with an aluminum motor (block, heads, intake) and there were 69 of those made for the public, however there was also COPO 9561 with came with the cast iron block and heads and aluminum intake (L72 - 427/425 motors) and we're not quite sure how many were made probably in the mid to upper hundreds (it's easy to get crucified on that point!) In 1967 and 1968 the Supercar dealers that you mentioned basically converted a factory SS big block car (small block in some early cases), usually 396/375 horse cars into the 427 Supercars. In 1969 all the Yenko Camaros were COPOs...double COPOs at that I believe - COPO 9561 (cast iron 427) and COPO 9737 (15" rims, 140 speedo and a larger front stabilizer bar). While in 1969 the other Supercar dealers for the most part were still doing conversions and didn't use a COPO car. Most Supercars started life as an SS which could include the RS package as well...a member on this site has a '69 Nickey Camaro that started life as a Z-28 and had an L88 427 transplant. If you check out his website and read about his cars it will probably answer a lot of questions you have. This is just a quick start and hopefully the real experts will chime in and elaborate on your post.
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Here is his website....
Supercar's website - click here
Anybody can correct me if I'm wrong anywhere....not that I have to tell any of you guys that!... [img]/ubbthreads/images/graemlins/headbang.gif[/img]