the best thing to do is DATA LOG what the 15deg pump does
after the inj install...
http://www.swampsdiesel.com/site/how_to_pdf/pdf/hpop.pdf
a 17deg pump only flows 6% more than a 15deg pump...so if his 15 is weak...you could try a 17 and retest it...it may improve..it may be worse.
and we have seen plenty of
modded stock pumps (sold as performance HPOPs) hold no better pressure than a good factory pump...
there's farrrrr more variance between ANY TWO particular pumps than the difference b/w a 15 & 17 deg pump...
We're dynoing an engine today with multiple (new) 'modded' stock pumps with some of our small single shots...to see how consistent this batch of pumps is...