07 Tahoe LTZ, K&N intake, pacestetter headers, cat delete, dual exhuast wheatley tuned. I am looking at pulling heads and possibly doing variable duration lifter, roller rockers, pushrods and maybe some more little things. You guys think it is worth it ?

 

what is the "variable duration lifter" ?

a cam swap will worth it, but in your case, with a 4 speed i mean, you need 4.10 first then cam/stall and put some money in the 4l60e