Anyone know what the max lift is on these stock springs?

 

Stock.

Don't even consider leaving them in if you upgrade the cam.

 

Ok, is there any spring that i can run that does not require machining of the heads? looking to run around 500 lift

 

It's your clearance between the underside of the retainer and the top of the guide seal that will be the limiting factor on a factory head. Usually they hit eachother around .470", give or take. Without machining your only other option is to run a set of +.050" keepers (which brings it's own set of issuess) or grind the underside of the retainer for additional clearance. Another board I frequent they refer to this as the "ghetto grind." It sounds cleap as heck, and it is, but there are multiple members who have done it with success in mild builds. There is some extra meat under there that does basically nothing and is just along for the ride.

There are other choices like spring and retainer sets (notably beehives) that can also give you the clearance you need, with other benefits, but also substantial cost.

Your choice- you pays your money and you takes your pick!