Hi!
Are you sure that the block is B21? I remember that -83 was the last year they made B-21. The head has marked castinc year above 4 cyl. in the exhaust side. The block has serial number behind the distributor, there can be marked engine type ( not always). You can look the distributor number, and find out in VOLVO`s green book which engines it has fitted. Also there is a metal ID plate in the right side of the engine room ( looking car from backside ) There you can see which engine and tranny it has fitted originally, also facturing place and year is marked there. B- 23 has 398 heads in factory fitted (405 in GLT`s). (160 has smaller burning room). All these systems CAN be different, in overseas cars. I think local guys know those things better. Hope this helps just little.

Yrs: WEBERMAN