1965 barracuda rear rear end?

Yep, Sure-Grip was an option regardless of engine. So until late in the 65 model year ALL a-bodies had the 7 1/4" rear, so if a Sure-Grip was ordered it would have been a 7 1/4". I don't know if they still did that after 66 or just installed an 8 3/4" if the Sure-Grip was optioned. At any rate, the Sure-Grip 7 1/4" is only marginally stronger than the open differential, and parts are rare as rocking horse sh*t.