Yer last response was a little confusing to me. Yes, your motor is a '76. All motors ('69-'78) have the same spacing. Difference is...'69-'76 have an exhaust spigot which is attached to the exhaust port by 2 counter sunk bolts. The exhaust pipe then slips over the spigot, then is attached by a finned split collar and is secured by tightening the bolt on the collar. The later style ('77&'78) has studs coming out of the cyl. head. The exhaust pipe fits directly into the head and is secured by a solid finned collar and a special spacer thingy that I can't recall the name of right now, then is secured with two nuts.
Your motor is a '76, and if it has studs coming out of the head for the exhaust it may have a "late model" head. But most likely someone just put studs in it to accept an affordable late model exhaust.