I hesitate to endorse 2" worth of lowering blocks. By creating a 2" lever between the axle and the spring, you have the potential for brake hop and axle wrap. The extent of either is based on the spring design, shock setting and tire grip (no way for me to say for sure).
Alternatively, I've run 1" blocks on a max effort road race 1st gen with no problems. One potential difference there is the leaf springs are highly biased to the forward half to resist deflection.
Play it safe and have the springs dearched for an 1-2" of ride height then fine tune it with blocks.