Looks like a 4-71 GMC blower off of a Detroit Diesel.
These were used to clear out the 2 stroke engines of exhaust gas. They are quite plentiful as cores, but the rotors usually go the wrong rotation to use on a 4 cycle engine. Most of them need serious rebuilding to work at all on a hot rod.
Jeff


Originally posted by Capri26i
Greetings from snowy Finland,

I'd like to know what type/size of blower is the one on that picture?

I think it is a 4/71 roots blower, am I right?

Thanks for answers.