this engien I am taking apart is a 12a, it came out of my '79and has the S1 EGR housings, Im guessing it is an egr engine. it does have the recycle thing on the intemediate plate as on the S2's and stuff, but what got me was it has 19 tensioning bolts ont he back plate, unlike in the haynes manual showing 18,
it says R5 on the intemediate plate next to the oil fill neck, and it says 3B on the back plate.
anything? my best guess is its an egr engien, the car was from cali. but i dont know any of this guru stuff

 

this engine also has an oil pump chain tensioner, not included in the haynes,
any guess's it has egr housings for ure witht he solid blocks ontop rathe than the I.