I'm going to guess that all conversion kits are for half ton trucks. Given that, your larger wheel cylinders require a larger volume of fluid. If you used the available boosters, you'll have a lot more pedal travel than you're used to. If you convert to a tandem master cylinder, then that will theoretically make up for the loss of volume, as you have 2 pistons moving fluid. As far as effort, a boosted 1" bore will likely still require less pedal effort than the manual 1.25 inch bore. There are factory one ton boosters out there, and at the last I knew, still at least one outfit in L.A. rebuilding them.
