I have a 1977 Dodge BB 400 RE-RING?

when you get new rings they NEED TO BE GAPPED .You can do this setting the compression and oil scraping rings by setting them squarly in the cylinder and then taking a feeler gauge and measuring the "gap " thats left between the rings .If there too close you get a special file and then file off whats necessary Now if you have too much ( which in most cases you should be within tolerance since the miles are low) If you measure the ring gap and its within tolerance no filing is necessary ) You were already on the correct thought of checking the gap by placing in the bore What type of honing tool dod you use a "dingle berry type " or the stone type The stone type ( with three expended stones ) will remove or could remove a lot of material The beaded one ,the one with a bunch of "balls"on it while it can remove some material its not under spring pressure so it will not have any pressure under it The ball type is a safer bet to use If you have not done the honing Use the BALL brush type and not the three stone type .You should bore mic it too But at 35 k miles The ball brush would be safe to use .You always want to "clock " the ring proper too But check the ring gap By placing the rings in the bore without the piston Check that gap You may need to do NOTHING at all Check the gap FIRST on each hole write it down and assemble it if its within tolerance file only as necessary and DO NOT listen to the negative feed back Check the gap file only as needed I think because the low miles You will still fall into acceptable gap tolerances But if you are on the high side or close to it Meaning if the gap is almost at the limit even on one hole You may seriously need to bore over .010 Those stone type honing tools can be a serious issue cause that spring pressure behind it can remove way too much material Always use a dingle brush type on a low mileage or low use engine and NO you cant buy over sized rings and use them You can buy std rings that NEED to be filed There will be or usually almost zero gap Which MUST be gapped to proper tolerance check JEGS and SUMMIT racing They sell rings for this purpose but they MUST BE PROPERLY gapped every set of rings The compression and oil scrapers will all be too tight when new NO .10 rings or the like STD bore only and not "pre gapped or "fit " Dont listen to people who offered opinions or disaster scenarios .Its not uncommon to refresh a low mileage engine in a RV make sure you get gap to fit rings and the right tools to do it Never too tight either Dont go to the minimum either stay just outside the minimum gap Do not build it too tight is what i am saying ALSO TAKE THE OLD RINGS AND CHECK THE GAP ON ALL THE HOLES PREFERABLY WITH THE RINGS THAT WENT INTO THE HOLES YOU TOOK THEM FROM IF YOU NUMBERED ,as you should have the rods and pistons then check the gap on the old ones too this way you have a idea of where your engine was really at before and after

An engine with 35k on it doesn't need to be torn down, especially by someone that thinks you need to put over-size rings in a standard bore.

Unfortunately it sounds like you've already started so just get a good gasket set and put it back together before you have a big pile of paper weights.

Go with file fit rings and set the gaps to oe specs. There are 001 over rings.

Why would you want to do that? There is no way you can hone the cylinders accurately enough to say the cylinder is the same size throughout. So if you get oversize rings there is no way to end gap them. And if you get it wrong you score the walls up and ruin the piston as well. Where do you get your ideas?