You mention wanting to put together an AMT '68 Camaro with a big block. You might want to consider one of the Revell '67 kits released in the last couple of years. My reasoning for the Revell kit is, in my opinion, a better proportioned body, it has a big block in the kit, and I think they even offered slicks as an option. Sometimes this can be easier than trying to mix parts from a lot of different sources. The changes for the '67 to the '68 are very minor such as side running lights and removing the vent window post. Revell has just released a new tool '69 Camaro that also is a big block kit.