Have searched forum for answer to this but no luck .
My early 18 has both heads with offset plug holes!

What can I replace them with to have central plugs bearing in mind hexagonal barrels?

I could get these filled and re profiled etc but its added expence.
Any aftermarket reliable ones?

I am doing this as part of total re build and considering all costs and wether its cost effective.
I looked at the 300cc conversion also a lot more dosh with pipes 2k ! and some queries on hail seizures too and as I thrash the bike round Silverstone gp a couple of times a year it must be sound ,
Any experience of 300 would be appreciated.

Fastfill