Alright you guys, I spent some time on the phone today trying to locate the new HT2011R lifters...no luck, Summit does not have them in-stock until Jun-1st. Even called FederalMogul (SpeedPro, SealedPower parent company), got a real friendly tech on the phone, described the situation to him but he didn't have any technical details (sizing, etc) on the lifter components. Not wanting to just sit there and wait I carried on...call me crazy, but here is what I've done:

1) I could not measure the ID of the lifter body machined grove (this is where the clip is retained within the lifter body), which meant I did not know the exact 'Grove Size Diameter'

2) I took a peek at my CompCams hydraulic roller lifters (retro-fit) and as it turned out they were using the snap-ring retainers, so off I went "sacrificing" one (well, I carefully removed the snap-ring)

3) I measured the dimensions of the ring, trial fitted into my HT2011R lifter body, it worked perfectly, once installed in the HT2011R lifter the snap-ring 'Gap Width' was exactly the same as when installed in the CompCams roller lifters, thus my conclusion that the "fit was right"

4) I hit on-line, maxing out the Google search engine (LOL, I'm an IS guy by profession) lights dimmed everywhere...eventually I came up with the RotorClip site (rotorclip.com) where a massive amounts of data is available for these snap-rings, and many other types

5) I measured all the lifter body, plunger, CompCams roller lifter snap-ring dimensions and easily, I mean I didn't even break sweat on their site (RotorClip), matched it up to the HO-68 snap-ring...I've attached the PDF drawing and their snap-ring catalog pages just for kicks...but it sure looks like this snap-ring is the right one.

Sooo...I'm hitting Fastenal tomorrow in hopes of being able to order a bunch of these. If I can, I will be able to re-use my lifters with the improved snap-ring retainer!!!