i found me a 66 valiant

how do 383 bigblocks fit in these little a bods?I have the chance to get one thats ready to reassemble for 200.00 with a rebuilt 727.The engine was built about 20 years ago,run one season at the track,then dissasembled for inspection.The engines owner got a 440 for cheap,so he greased the 383 down with wheel bearing grease and stored it away.It has 509 cam,2.14 intake valves,hooker headers,eddy intake,etc.