Carrillo rings.

My CP pistons came with NPR rings. I can't find any good info on ring end gap for these rings. NPR was no help and still waiting to hear from Carrillo.
top ring MG10-4505
second MS20-4505 THG
oil ring D30
Anyone have any info on these rings they can share?

I can't help you in this type of application, but...
I use a lot of Nippon rings in MX related builds and have found them to be of excellent quality in comparison to some others I've used for those types of builds.....55-75hp @ up to 14k rpm 4 stroke and 30-60hp @ up to 10.5krpm 2 stroke
They are generally about 2.0mm and low tension in those applications, but I've never had a quality or blow-by scenario that I could blame on thise rings.

NPR has been an OEM supplier for many Japanese brands (car and motorcycle) for decades, IIRC. Quality should be right up there...

Gaps shouldn't depend on brand; check whatever the recommended gaps are for rings w/ your bore size w/ different companies and I'll doubt you'll find much difference.

That is good to hear. All i found so far is .0055/inch of bore. I would like to verify that number before i start grinding. They are steel gas nitride rings.

Search: "Mahle pr-40-16.pdf" and see the gap chart on page 21(pages aren't numbered, but it is 21 by count)
Depending on your ring thickness they may have specific recommendations.

the ring thickness is .043/.043-3mm oil ring.

Rule of thumb for N/A street/strip = .0045 per inch of bore.

.0055 is for nitrous use.

The only chart I found listed ring gap for these rings at .0055 and .0065 per inch of bore for N/A more than 600hp, but less than 750. I assume my 572 will be over 800hp.

This chart chart from Mahle may help:
(Note: Mahle's gas nitrided rings are 9254 steel)

Bigger is better then tighter

I gap my new 572 C.I. B1 NOS motor with .4.500 bore with .030+ on the top rings and .034+ on the second rings racing with E85 fuel and two NOS kits with around 450 HP total for them, 1000 HP on motor
I'm hoping that is wide enough

I figure in my app should be .020-.022 top ring and .022-.024.

Are you building this engine yourself?

Your application is not Drag Race Only, it is Street/Strip. My info, which I have used for decades, agrees with Mahle's chart.

But it is your motor, and setting it your way won't hurt a thing. Looking forward to see the rest of your build.

Yes, a life time dream to build and run a Hemi. First Hemi for me. As a hobbiest, I have built 4 sb mopars, 1 BB, 1 sb Chevy and a 400 Pontiac. 1 sb mopar did not survive, had an oiling issue and came apart on the Dyno after 45 minutes of run time. Trying to be sure to get everything right and no failures. I can’t afford any mistakes with this one.
I’m building this short block in the basement where it’s warm. Here’s some pics of my little work area.

that is what i have been told as well.

as to being tighter, well, no one will know if you are little bigger on the gap, but everyone will know if you are a little on the tight side when the rings butt together !

Spoke with Ray Barton today about the ring gap and bearing clearance. He suggested .018 on top ring and .035 on second. Said he has ran many motors that way and some to 10,000rpm and never an issue. I'm reading .015 is all thats needed on the oil ring.
The rest of the combo will be Stage V twin carb intake that i had drilled for carbs to set sideways and will have 2 850 Thumpercarbs. Heads are Stage V fully done up by FHO and flow 442cfm@.700. The cam is a Bullet solid roller with 275/278@50 and .736 lift on a 110. Compression was suppose to be 12:1, but my numbers calculated are showing 11:1. I will have to double check that. Just assembling the short block for now. Will finish in a year or two when im retired.

I understand the theory behind bigger second ring gap but wow! That's a lot.

Fwiw I ended up lower than intended compression as well. At the end of my build I checked piston to head clearance with solder and was able to bump it up with a thinner gasket. (and also smaller bore gasket).

To that I mean, I have a 4.31 bore and ended up ordering gaskets for a 4.28 bore with Cometic......

I'm not gonna follow Ray Barton on this. Best suggested .022/.027 and .020 on oil ring. This looks like a better recipe for success. CP spec sounds kind of tight as well with .0045/inch of bore.

That will work.

I like your nice and clean, comfortable engine assembly room.