First Lingenfelter car pricing

[Mcmahanjoe]

I've got a 1977 elcamino (383ci) that was one of the first if not the first car John lingenfelter did as an installed drivetrain package. It is a survivor in near perfect condition. It is also the first fuel injected tpi car he did and was used as his test car while he perfected his fuel injection system. I have all paperwork including build and dyno sheets as well as the original returned checks. I need help determining value and have not been able to find comparable cars. Any help is appreciated.