All 1976 360 F bodys were 2 barrel, 999 (HD904), 8 1/4. The 727 fits without issue. By changing the lower shock plates to the standard non-iso (no rubber blocks) you can bolt in a 70 and earlier B-body 8 3/4. By pulling on the springs slightly it will line up. Only 3/8" wider per side. Standard 727 A-body drive shaft will work with the 727/ 8 3/4 combo. I've owned my Super-Pak Road Runner since 1977.
Doug