Engine sputtering at about 65

Just wondering if it was a square bore or spread bore.

I forgot to look, I'll go check when I get a minute, I had a ***** of a time getting to work, she was backfiring, sputtering, gagging and coughing the last mile of the way here. Good thing Jegs or Summit has cheap overnight shipping, I can have something here tomorrow if I can make a decision today.