Here's a recipe for valve springs, retainers & valve seals that no machine work is required for iron Vortec heads and its less than $130.00 to do. These are Summit's part numbers NAL-12499224 LS6 valve spring kit. $ 60.97 CCA-787-16 16pc. Retainer set. $ 51.97 These valve seals I bought at an auto parts store, I think they were about $ 15.00 Fel Pro SS 72861 The valve springs are bee hive springs. If your using a flat tappet cam these are great for that application because the open spring pressure is below 300 lbs. Without looking it up right now there about 285 lbs. open spring pressure. They drop right in the spring pocket or I should say there a tight fit but they are the correct springs. The retainers are Comp Cam an they fit the OME valve stems an locks. I reused the locks I had cause they didn't have a lot of miles on them, bought them new a few years ago. If your unsure about your valve locks buy new 7° locks, there cheap. You HAVE to use these retainers with the bee hive LS6 springs or you'll run into rocker arm issue's. The Fel Pro valve seals come with a soda straw looking thing with a round end. Oil the valve stem, put it into the valve guide then put the soda straw on top of the valve stem when the valve is all the way up then drop some oil into the valve seal on slid it onto the stem to the valve boss. Don't let the valve stem slots drop into the seal, remove the soda straw. Those slots on the valve stem have sharp edges on them an will damage the the seal. The valve seals need to be lightly hammered onto the valve boss. They need to go all the way down on the boss until they stop. I used a socket to put them on with, think it was a deep 7/16 or a 1/2 can't remember. I did notice that some of them weren't as deeply set as others were so I went back an reset them all until all were the same, they will stop going down an some point. Take your time an hammer lightly. Anyhow these are the springs/retainers/seals I'm still using to this day. You can get better springs than these such as Comp Cam bee hives, there around 60.00 more but the way I look at it if GM is using these springs on there LS6 heads then they must be good springs. One more thing to check on once you have the cam in an heads torqued down is to check the gap between the spring coils when the spring is compleatly compressed, totally open. You must have a total of at least 0.60 between the spring coils combined, meaning if you can slide a 0.20 gap gauge between 3 or more spring gaps your good to to go. 20+20+20=60 or have a total of 0.60 some how.