A stock 454 tbi benches around 600cfm.....I've never seen or talked to anyone about the numbers of a modded 454 tbi, but it would definitely help. The O-ring type oiling system is the type seen on engines from before the tbi engines, the retainers have splash shields below them that helps keep oil around the top of the valve, the valve itself has 2 slots, one to hold the "keys" and the lower one to hold the O-ring. The tbi and vortec valves have single slots to hold the "keys" only, and have an oil seal that sits on top the valve guide on head. Usually if I'm changing the valves to 1-pc valves, I'll order valves with 2-slot shafts so i can switch to the older oiling system which allows .030" higher lift and better valve oiling. If you're wanting to keep your stock valves, you can take your heads to a machine shop and tell them you're wanting to switch from oil seal to o-ring valves and if the shop knows anything about performance engines, they will know what to do. The only thing you'll have to do is acquire retainers, splash shields, keys, and o-rings for your cut valves. They'll put the valves on a lathe and cut a 2nd slot below the retainer/key slot, which is where the O-ring will mount.
