Original for a `76 would have been 99H/889/AJH probably.
This is a 998 block (dimensionally identical to the 3x 1098 ones you have already).
Whether you have grief using the others depends on the inspector and his view of the Mini world.
They can take a dim view if the replacement engine is older then the original, as all of yours are.
OTOH, some just don't care about these semantics, as long as there is a receipt for the motor and all engine & body numbers are in order.
They take the view that a 998/1098 Mini block is a 998/1098 Mini block (same) and argument is confined to the stamped impressions on the top.
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
