Well on a 383,aluminum heads would be a good idea if the engine has at least 10-1 compression.An idea for the 327 would be a Vortec head kit such as Scoggins-Dickey pn SD8060kit,and a comp cams 262 Extreme energy cam and lifters.This ,in conjunction with the headman header and a 600-650 carb.will make quite an impressive,tourqey power plant.Those Vortec heads are by far,the best bang for the buck for a small block.That cam will work with the stock springs that come on the heads.Cheaper than a new engine,even if you have to freashen up the 327 short block and more fun than a barrel of monkeys.Something to consider.