Does it have a regular (stock) prop valve too, or just the adjustable?
If its just the adjustable, then you'll have to be pretty careful on the brakes as the rears will definitely lock first.
Also depends on the conversion kit, is this a primarily stock parts type conversion, or all aftermarket stuff? If its a stock type kit and uses a regular prop valve in addition to the adjustable, then you'll just be back to the "stock" balance, which was rear biased. If its aftermarket, with different calipers and no stock type prop valve, if you have larger calipers (or more pistons) they might take more fluid than the stockers, and the bias could be pretty severe to the rear.