650 might be a little on the high side but i would expect >600 for sure. the engine in my car is similar 451, eheads, 11.5:1 cr, hp950 on gas, m1 single plane, 275°/.575ft cam. you have more cam, cr, carb and on alky those things should make more hp for sure. last time i weighed my car it was around 1575 without driver. some things have changed but the weight should be close. i figure minimum of 1750-1800 on the starting line and it regularly runs 160 which i figure would equate to around 600hp