With a cam of that size Use the stock LS6 valves, with suitable springs, mill the heads .005, a good port job, and do a nice valve job and be done with it. Keep your stock rockers do a trunnion upgrade on them and have as much fun as you can. You will have a very light and stout valve train.

 

thanks man. all i was looking for was a straight answer like this

 

853's are ok ported but not as good as 243/799 castings. There is at least one set of 243's on the classifieds now with I believe the the hollow intake/sodium filled exhaust valve. Personally I would run stock valve sizes or go no larger than 2.02/1.57 valves. It is just not needed on a 346/347 ci motor.

And as stated above lift has little to do with PTV and more with duration, LSA and advance as far as a cam goes. Then milling, HG thickness and valve size needs to be considered......