Diesel Bombers - LB7 pump INTO a LBZ no not a typo

i am going to replace my LBZ pump with a modded LB7 pump that i have opened up. due to emergencies and i without a doubt i will knowingly have to endure the hell i only knew 6.0 psd to posses again. lol i was hoping some of you with modded lb7s can give me some rail psi number to see how much less if any will this modded lb7 pump and lbz FCA. will perform against stock lbz. this might be a bad idea but this is the only idea that i have left so...... here goes some fun and lots lots of work
TBC