['ol Pinion head]

Most common code '71 455 4bbl Dport engine block...
As original assembled engine: 2 bolt main caps, 66 casting press in stud heads, a "2072" single points distrib,, & a "1262" Qjet. Late in '71 model year, unitized distributor became optional distributor.

While the '71 YC was ordered in a few '71 GTO's, A-bodys, & Formulas & model J GrandPrixs, the VAST majority of '71 usage YC coded engines came out of B series cars. '71 Grandvilles came standard with a YC coded 455. Majority of '71 Bonnevilles came with them as well (occasionally will come across a '71 Bonne with a 455 block code YG). When a '71 GP was ordered with the SJ option, the 455 YC engine was standard equipment.