The stroke is the same on 5.3L, 5.7L, and the 6.0L. You'll run into balance problems if you mix and match cranks from different bore sized engines unless you have it balanced for the parts you are using. It would be better to get a matched 5.7L reciprocating assembly from someone who already did a stroker kit install. With overboring your block double check the boring prices, to bore ~.120" or whatever size to the 3.9" bore they will more than likely need to make multiple cuts which may up the price.

 

Boring/honing cylinders probably costs about $20-30 per cylinder. The Lunati 382ci stroker kit is about $4K (pistons, crank, rods).

It would be cheaper to bore the block to 5.7L if possible (3.90" bore), add forged pistons, stock LS1 crank, billet rods, and spray the hell out of it. I'd convert to a wet kit for over 100 rwhp shots.

Tony