Trying to build power....225 step by step help

Guys guys guys....sincerely i understand thats its rare , 1 of 482 , but it will take 60-70k to make it worth maybe 30k if m lucky , i rather inject i dont know 10k and call it a day and have fun with it . No original engine , no original nothing was included with the car , its a rusted shell and i have doors ,trunk , hood and little body parts , it as still its fender tag but it needs everything , so i want to have fun and wont put a fortune , just wanted to be different, already my 71 cuda will run a 5.9 crate with plenty of power..i was like why not put a slant 6 back into that challenger and kick ***....i was even thinking to put a 3.9 v6 with a 5 speed , but i cant. Need money for sandblast and new sheet metal we will see whats gonna happen , just hope i wont get fed up.and sell it.