Comp cam 265LrRR12

specs at 215/223 @.050"
.607/.61 lift
112 lsa / 110 icl


99 silverado 5.3 ext/cab 4x4, shortys, true duals, k&n cai, superchips(good scan tool lol), vette servo, stage 3 shift kit, 4.56's eaton posi, 33's very heavy truck but still will take a hemi anyday

i want to keep stock converter

 

Should work OK. However, due to the size of your tires and the weight of your truck, your 4.56's are the only thing keeping me from saying that a bigger stall would be needed. If you have any intentions of increasing tire size you might consider something a little more tame (or a small stall). Also, if you are running stock heads the additional lift is of no real benefit. The flow on the stock heads tapers off significantly over .500" of lift. The .6xx lift cam that you listed will put a lot of additional stress on your valvetrain for minimal gain. Lastly, a tune will be required.