Need some help / ideas for a 3/8" NPT boss to mount my IAT sensor into my airbox. Is there a compatible thread I could use? - doesn't need to seal, just retain robustly.

Or anyone got a lathe and a 3/8 npt tap....?

Can't remember how to make a proper linky but this site has any number of bits that should do the job

http://www.earls.co.uk/earls/adapters/adapters.html

just seen how this appears in the preview - just a 3/8" i need not a 38"!!

Have you checked the ETB adaptors. Try ETB instruments website.

thanks - will go and try the local hydraulics place, and if not the above two.