1.6 exhaust valves
 

I have an 01 ls1 I'm about to do h/c swap on, picked up some ported ls6 heads and have them at a shop to be gone through. The valves are all stock size I'm wondering if it's worth it to go up to 1.6 on the exhaust valves? Is it worth it since I will need new exhaust valves and cost more for the extra machining?

Not sure why you need new exhaust valves. The stock rocker on the LS1 is 1.7:1 and I assume the 1.6 ratio you are referring to is for a SBC. On the LS6 heads, if they have the lightweight valves don't replace them.

Oh sorry Not the rockers, I meant the exhaust valve size itself stock they are 1.55" and I was wondering how much different putting a 1.60" exhaust valve in makes

Depends on if the heads have been milled. If they have you will most likely have to flycut your pistons a little for needed clearance. You can usually rent/beg/barrow one fairly cheaply locally or on board.