Your 383 will have a centre sump and weigh about 625 lbs. More than a sbc but less than a bbc.
Did you know you can bolt the whole front suspension from a 71-87 chev truck on to your frame.
Easy way to get discs. You'll need to swap the rearend or axles to get the same 5 bolt wheels to match the front though.
Here's a link for motor dimensions to compare.
Popular American V8 Engine Dimensions