[Mg-mmm] oil pressure problems

[DB35PA at aol.com]

Filing system has collapsed... I've seen the picture and details a hundred  
times and now I can't find. (Nope, not in Blower) 
 
What is the correct clearance (with feeler gauge) between idler gear,  pump 
spindle and oil pump body for PA? Blower says same pump for P,F,K,L, KN  & 
N. 
 
What's the correct pressure for  by-pass relief valve spring? Any  sources 
of replacement spring on this side of the pond? 
 
I have 45-50 lbs. oil pressure at cold start but continuous driving shows  
falling pressure... and at temporary stops, it rapidly drops  dangerously 
low at idle... and constant "blipping" of the throttle is required  to keep it 
above 5 lbs. Scares the hell out of me. Any thoughts? Am I looking in  the 
right place for starters?
Thanks 
Don B.