Hey, I know, nobody wants to admit it BUT with LS2 Blue GM Performance Parts springs #12625033 ($55-60 new) and Comp Cams retainers #787-16 ($49-60) with stock push rods. I had one in a square body S10 with a 3.73 gear went quick enough they asked my to not come back to the strip without a cage. I currently have another in a 1978 El Camino junkyard wars beater drag car. I know what the internet says, but, with stock valve seals .580 clearance, the retainer that works with the beehive springs give you additional clearance to the guide. I am running the 1.6 self align rockers on an LT4 Hot Cam at .492 lift and that makes for .525 lift.
The one in my junkyard wars 'Hell Camino' is wearing a Volvo Penta Q-jet intake to have a stock appearance. Look, it works, we measured the set up on at least six heads, all around .575-.580 from the Comp Cams retainer to the OEM seal, not just the guide. The Hell Camino has genuine cracked heads with at least three types of block sealer and stop leak in it. I pulled the motor from a dead Suburban at an LKQ yard, honed the cylinders and plopped in the cam, I also cheated a little more by using steel shim head gaskets...
