You best book in with Simon for a bit more time so he can tweak it properly, I remember seen this in the past thread of previous owner and surprised he didnt go higher with the boost as it surely has more available.
You probably should source another A14 block to keep withing the rules of engineering so just get and A15 crank, rods, sump and E series pistons made for it A14Force has some good turbo slugs with HPC coating available
http://datsun1200.com/userinfo.php?uid=2430 for PM and heres a link to them
http://datsun1200.com/modules/myalbum/photo.php?lid=20418That way you have the extra 100cc to help with earlier boost.