Eric_Paulsen

I am new to this so forgive me for maybe asking a dumb question. I have stumbled on a 65 Cutlass convert that appears to be a 442. All logos are there and such. Definitely a real looking engine. I can see that it also has had some things done to it over the years that are not original. The question is how do I know if this was a factory built 442, or one that has been cloned with real parts? Which numbers or what ever should I look for? Thanks for the help!