B vs RB

As a visual aid in determining the difference between a 361 and a 383 : there is a stamping next to the dizzy . On a 361, it will be stamped "361" or "36" followed by the date code . On a 383 , it will be stamped "383" or "38" followed by the date code . Also, following the stamped number there should be stamped a letter "R" or "P" . The "R" stands for regular fuel or 2 bbl. carb. while the "P" stands for premium fuel or 4bbl carb . ALMOST everything can be exchanged from a 361 to a 383 and visa-versa except the pistons .