Converting to a big block is not cheap. Do a search and you will find all the "other" things you would need. Why swap out the 383 ? IMHO I would spend my money on upgrading the suspension and getting the 383 to hook up. Eric68 should have lots of pointers for you.
69 Camaro -originally a LM1 car. 327, Edelbrock E-streets, hooker, DUI performance distributors, ultradyne cam, stewart, TRW etc. Vintage Air, AGR steering, Corbeau GTSII seats, 700R4 transmission, 12-bolt w/Eaton 4.11:1