cab and chassis specs??

[bigoates]

Hi does anyone know the frame specs for a 79 chevy cab and chassis? My friends truck had an ambulance box on the back of it originally but has since been removed.

Thinking about turning it into a crew cab with a flat bed to use as a mean hauler for a gooseneck trailer.

I looked around and couldnt find anything on it.

Not sure but I think the frame loos to be at least a foot (if not more) longer than a reg long bed frame.

Thanks!