I' m not sure this will help but I will be delivering some parts to the Tri-state Warbird Museum in Batavia, Ohio on Friday June 18 and will see if they'll allow me to shoot some shots of their P40M. It is currently under restoration and should have its cowls off.
As for the Merlin powered P40F, do a google search for Judy Pay P40F. She is in either Australia or NZ and owns the worlds only P40F. They had to fabricate from nothing everything from the firewall forward as it is completely different from the Allison powered P40s. There was almost nothing in the way of original factory drawings and documentation on the Merlin cowling and associated structure to work from. A very interesting story of a 20 year restoration.