For unleaded fuel, you really need to install hard exhaust seats, they require either B20E exhaust valves or better, so you go to the guides that let you put the smaller stem B20 valves in, this adds up to a lot of money, and you can't go back and weld the head latter.

Alternately, you leave the compression low and drive it casually and you won't need to spend all that money. It's the chamfer on the top of the guide that is the primary oil seal in a B18, you need 4 for the intakes atleast, but they are cheap. With the money you save, you put that towards your future performance/economy engine build.

Actual 10:1 B18B don't ping because the timing is fairly retarded throught the rev range and they still demand 100 octane to do it. The thick B18A/D head is desirable for porting for performance too, but once you mow it down, it's usefullness is limited.
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69 142S Overdrive + 69 164S Manual