Not sure if you'll be able to find a stroker kit or not but it isn't too hard to build your own. A 572 requires a 4.500 stroke crankshaft which you can get from SCAT, Callies, Molnar, etc. If it was me I'd use the Chevy 2.200 rod journals and then use a 7.100 long connecting rod. Then you just need pistons but those shouldn't be too hard to find. Diamond, JE, Ross, Wiseco, etc. can take care of you.