Hi Geoff, I have done a bit of research for you....here is what I have found...Click HERE and scroll down to a post from timcut, post #14.
He mentions finding the air filter from a Detroit compressor will fit with little modification. Also for some technical details on the 270...Click HERE
Hoping this may help,
Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member. Kindest Regards, Darryl