First 1967 383 installed in a Barracuda

A56 said
From what I understand the 383 in 2nd gen Barracuda's and Dart's was a B block compared to the taller deck RB 440 in the 69 M codes and limited production 68 Dart.

Yes. 383's are B blocks as well as 350's (in 1958), 361's and 400's. Exception to the rule "back in 58 and 59 there was a RB 383. "