imho you should disassemble the engine first to discover what is needed..
1st generation has different cam, lobes were ground differently and slightly higher rise which I believe is responsible for increased horse power over 2nd gen Rebel.. 2nd gen head is a downgrade
Differences in cylinders that I have noted 1st gen used 4 dowel pins and 3 stud gaskets
Buy OEM Parts for Honda Motorcycle 1987 Cylinder Diagram
While the 2nd gen cylinder used only 2 dowel pins and no stud gaskets..
Buy OEM Parts for Honda Motorcycle 1996 Cylinder Diagram
1st gen members who have ordered Head Gaskets have received 2nd gen gaskets.
Two of the head gasket holes are too small to use 2 of the dowel pins which can be discarded..
unproven Big Bore cylinder may be a waste of money and you won't hear from Elchico as he was able to get himself banned within 3 weeks of joining..