Bobw and Johnny
Thank you for identifying the exhaust relief baffle and showing that it is on the 1955 parts list . The model number on my mounting clamp is 15016, which corresponds to the 1956 parts list. Also the exhaust housing part number is the same for 1955 and 1956 (p/n 376406). Looks like the exhaust relief baffle was just deleted for 1956.
Unless someone else knows better I will leave the exhaust relief baffle off when I reassemble the motor.
Thanks again.