CORRECT HEADRERS?

CORRECT HEADERS?

I AM GETTING SOME MAC HEADERS. I WANT ONES TO FIT ON CAST IRON GT-40 HEADS NOT P JUST REG. MY QUESTION IS ARE THEY 1 5/8 OR 1 3/4 I AM GOING TO USE A BBK OFF-RAODS H PIPE WITH MY FLOWMASTER EXHAUST. NOT LOOKING FOR PERSONAL PREFERENCE JUST THE ONES THAT FIT CORRECTLY. THANKS IN ADVANCE.

(EDIT) EQUAL OR UNEQUAL. SHORTIES

THANKS I APPRECIATE IT.