how strong is stock crank im doing motor this winter and putting forged rods and pistons. i want to put a 200+ shot to it and im wondering if it will hold up

 

yes it will no problem

 

The factory crank... I'd throw 1000hp at it all day and then some! There are guys in the FI section doing 8s maybe 7s 1/4mi with the factory crank. This has been discussed many times and apperently nobody in the FI section has heard of one breaking due to too much power. Also it starts to felx a little around the 1000rwhp mark.
Just get your internals balanced and you should be fine.
Goodluck!

 

I wouldn't worry about the crank. The rod bolts are the weak link.

 

I agree, rod bolts which should come with the rods anyways. If not get them and you'll be absolutely fine.

 

I've yet to seen an LS1 crankshaft grenade itself

taken them over 1,000hp few times.