Today there was a guy i know told me that i should put a 383 crankshaft in my 400 chevy small block cause it will make more low end torque so i was wondering is that true? will the 383 crank go right in without any machining? or is it better to just stick with a regular 400 crank?

 

No

A 383 crankshaft is a 400 crank with the mains turned down to fit into a 350 block. The 400 has the longer stroke so putting it into a 350 engine can make a 383.

There's no way to increase the stroke of a 400 without using an aftermarket crankshaft and doing clearancing to the block.

A 350 crank or a 383 crank that's been turned down to fit into a 350 block can be installed into a 400 by using bearing spacers. A 350 crank in a 400 block is a shorter stroke and makes a 377. Large bore, short stroke makes good HP but not much more torque than a 350 would make.