It’s going to increase fueling a lot across the board, it’s not like the fuel screw which is changing the stroke of the plungers by fractions of a millimeter, it’s almost doubling the stroke of the plungers. These pumps were not designed to idle with that amount of fuel, and with no leaf spring you would be looking at anywhere from 110-130cc of fuel, depending on the condition of the pump so I’d really recommend an intercooler and larger than stock turbo along with studs for running that much fuel. But back to the idling issue, these pumps aren’t meant to idle with that much fuel delivery, the idle is controlled by the minimax governor, which controls the position of the metering valve, which controls how much transfer pressure gets to the plungers. The plungers displace the same amount of volume no matter what, so it’s up to the metering valve’s setting to control the flow to the plungers so you can get that 5cc to idle correctly. The problem you run into on these larger db2s is you can run out of adjustment quickly and you have to adjust the regulator for the transfer pressure pump to bring down idle transfer pressure as a way to cheat the flow down to the metering valve, as a way to get more fine adjustment to get a crisp idle and good droop setting. Issue with that, is transfer pressure affects your hydraulic advance, so you have to have a stand to be able to check your hydraulic advance and adjust the advance piston setting accordingly to get it back into spec, 6-7.5* locked at idle is what you want. Another issue you can run into with doing this without a stand is your return fuel volume, one of the bigger wear spots on these pumps is the advance piston bore to piston tolerance. This tolerance controls your return fuel volume, and when you increase your total fuel volume you also increase your return fuel volume. These bores wear out really quick because it’s a steel piston sliding in a aluminum bore. These bores need to be re-reamed after your main fuel is set to get your return fuel into spec, there are several oversized pistons available to account for wear but lots of pumps already have the largest piston in them already, I put a ceramic sleeve in them to go back to the standard bore size, and to eliminate the quick wear issues.