high 200s on hp, 400 something torque roughly, because those are the smog era 460s, its got a good block but the best iron heads to start with are C8VE (1968) - D3VE (1973). 68-70 i believe has the small 75 cc chanbers like mine, 71 -73 have 90 something cc chambers. with some port work, 68-73 heads are very good and can support about 700hp with extensive work done.
O and i hope you have experience with extensive motor swaps because this swap is a PITA. and if you have a budget like $5,000, add about $1,500 extra to it to cover everything and thats a mild build. but its worth it. mine is very street friendly.