Cracked block....recommendations?

When I did my 318 swap in my 66 it always had a mystery antifreeze "weep" it would go through half a gallon of coolant about every 1 1/2 to 2 weeks. figured it was the block drain plug threads on the passengers side, gooped em up, problem seemed to go away. Then I installed an aluminum radiator and flushed the hell out of the cooling system, problem came back. It didnt help that i slapped a fresh coat of paint on it as well. Its been like this for a long time evidently, because for me, its always seeped, and i know the guy whom i bought it from had the same problem. now that its sat for 5+ months the paint has flaked away and its pretty obvious now. Its cracked on the passenger side, perfectly centered between the front and middle freeze plugs, about 3/4 of an inch above the block drain plug. Really bums me out because this thing is so clean and runs so well, uses no oil, and is peppy as hell. I know a cracked block is nothing to putz around with, so im after some suggestions. Im thinking ill run this beast until i can locate a new engine...hopefully. luckily i have located a .030 over 318 shortblock with flat-tops, unknown cam (ill probably swap it out reguardless) Im going to go check out this monster to see how deep the slugs are in the hole and go from there. Anywhore, had anyone out there had ANY luck nickel-rodding a crack? i contemplated block sealer for about 2 seconds then slapped myself...cause that stuff is no bueno, and im not for ruining my brand new 200+ dollar radiator...so, save it? nickel rod it? block seal it? (*shiver*) run it? sell it for a derby motor?