FWIW...my 280 Denso lasted about 2000 miles.....mayb
e 3 years. It had an internal shorting issue. MY new DW pump,i understand, is asian as well. The aeromotive, i think, is american made. My in-car F/press gauge showd no variance... 43 line off,36 line on.so i dont suspect any return line issues. At 26/27lbs, F/P shows 68 (close enough as most gauges arent so accurate i read) BUT.... with the denso,on a full blast, (all things being equal ie;no changes) i had a steady 11.3 afr....which i was ok with and it ran well. With NO other change,a full blast with the DW shows me 10.75afr. Ok,....its a stronger pump up top so should i lower the base f/p some....or just turn the boost up
.... Would 40/41psi. f/p cause a problem? thanks