your head will need a lot of porting and poloshing to acheive good bhp figures imho as this is essential for the n/a build (incedentally cosworth originally intended the yb head to be for na) but had to close the ports slightly for turbo use as was deemed to wild)
thats why a stock head will need good porting to run n/a

also to be honest i wouldnt even bother with the 45,s mate bare essential to have 48,s in my experience ...

as for the pistons much easier to just buy a set specifically for the job


in a nutshell mate is near on impossible to build a decent n/a lump cheaply
oh and revs nicely to 10k


oh and i personally own a jondell specced n/a lump with gravel spek head and produces 235bhp on 48,s oh and revs nicely to 10k