How much is acceptable to have, engine didn’t smoke or any issues. Been sitting in my house garage for 25 years removed to put in the Lil Red so I pulled heads to clean out the ports (mice got in there) and noticed the ridge, maybe catch a fingernail on it, thought it was just carbon at first. 1974 stock cast crank engine.

It depends on what the purpose of the engine is. If it's a street car or a bracket car, as long as it doesn't smoke for have excessive oil consumption, it would be fine. On a tight budget SBC street rebuild, I put it back together with .007 of wear right under the ridge. The cylinder cleaned up half decent with a hone, except for the area right at the top that the hone wouldn't touch. It worked out okay, it had a little bit of piston slap when it was cold, but it didn't burn oil.
The bore tends to have the most wear right under the ridge. Since there is more wear there, that means there is taper. That affects ring seal. If this is a race engine where every horsepower counts, we want the bore to be perfectly straight and round. In that case you would need to remove the ridge, hone the cylinder with torque plates to make sure it is perfectly straight and round, and then measure to determine if you could reuse your pistons as is, coat the skirts, or if you need new pistons. If it's really bad, you would need to bore the cylinder.

If you can feel the ridge it has way too much piston to cylinder wall clearances to give you years of good service without worrying about it using oil and breaking a stock piston skirt
I would take it apart and take the short block to a good machine shop and have them bore and hone it with a torque plate and buy a good, not a cheap, rebuilder kit for that after finding out what bore size you need to order for that block

Will it run and work okay doing it the cheap way with quick hone and set of stock replacement rebuilder rings, yes it will Will it live and give you excellent service for a long time, not likely

It’ll be a weekend cruiser only. The engine came in the 64 race car (basically stock, they had removed the Max, I bought just for the car) it did run 7.70s in the 1/8 mile. Then I removed for a better 440. Ack then I had removed a head to see what it had but Disney see any ridge then.? Put it in a 70 Challenger, ran up and down road a few times then sold car pulled engine and it sat in the corner since 97. Maybe the 6 pac washed the cylinders down so much it wore the bore in that short of time.?!

I have seen more ring ridge on motors that were run hard before they were up to normal operating temp then on motors that were up to operating temps then abused. Take that any way you choose.

If you are not racing the motor, and it will indeed be mostly for cruising around, the biggest concern would be the actual ring seal. If there is a ring ridge, it is also very likely the rings have worn as well, which means a larger end gap, and questionable ring to cylinder sealing. I have in the past pulled motors like this apart, hone the cylinders, and replace the rings with new ones of the original bore size, replaced the rod bearings (and maybe the main bearings, depending on how they looked) and new gaskets, and have had great drivers with little or no oil use, for many years. Were it me and my car, I would probably go in this direction, but this process isn't as cheap as it was years ago.

The reality is if the rings are still seating on the cylinder walls after sitting that long, the motor will do fine being used as an occasional cruiser. The odds of a car used like that accumulating a lot of miles probably isn't going to be an issue. As long as it doesn't smoke bad, adding a quart of oil now and then probably won't be a deal breaker.

years ago they sold a tool called a ridge reamer and stiil do LINKY
very common back in the day. Ridge ream it, hone it, slap in a set of cast rings, resize the big ends of the rods, lap the valves, use good guide seals that clamp on the guide boss and run it.
Are you going to get 100k miles out of it? probably not, 30K easy if not beat to death.
I've known individuals that honed the cylinders by hand with emory paper, put in new rings & bearings and run it. My brothers 57 with a 327 4spd in it was done that way back in the mid 70's. It was their only car for many years. It was pretty much parked in the late 80's but still runs and doesn't use oil.
A lot depends on what ones budget is and use is,
I've had many customers due the full B&B on a motor that never sees the track or gets more than 500 miles a year on them. I ask why

I was going to do a valve job anyway so I’ll pull it down cut the ridge, dingle ball it and new rings. I’ll scotch brite the bearings while I’m at it

Why? Leave them alone and put them back in the same place on the crank and in the same rods that they were to start with

Leave the bearings alone.

How bout leave the whole thing alone and just get it running

Careful with that ridge reamer !

Yep. Good way to screw up the bore if you go too far....

Good push, I’ll do it.

i did the hone, rings and bearings thing to lots of motors back in the 70s & 80s. Some saw a lot of miles afterwards. I have a ridge reamer, but unless the ridge was huge, I didn't use it often. it was a royal pain in the butt. to use, then left a pile of junk to clean up.

My concern about just getting the motor that has been sitting for 10 years would be if the rings would reseat or not. Sitting a couple years would be OK, but 10 is pushing it. I've replaced a lot of motors with other used motors over the years, and that was my findings.

With a Mopar motor built before about 2000, new valve seals are almost a must.

I’m doing the valve seals but wondering how rings go bad just sitting over time? Rusting?

They will re-shine right quick.

If you are doing all that with the engine still out,
hook up to the starter to do a dry, then oil wet cranking compression test,
then a % air leakdown test.

Better to spot a bad cylinder before the work of putting the engine back in the vehicle.

If the motor has been sitting 10 years, the odds are the motor has not been turned over in that time frame either. The cylinders of concern are the cylinders that have sat for 10 years with valves open. Its hard to tell what may have entered those cylinders. The rings can and do stick to the cylinder walls, and the rings can and do stick in the piston grooves, and well worn rings can loose their tension. Carbon build up from when it did run can set up pretty hard over time, rust particles, if not bad, can actually reseat the rings, but if the rings get stuck in the piston grooves, they often will not free up with out being removed, and the grooves are cleaned. At that point not putting new rings in doesn't make much sense to me. Sometimes running the motor frees them up, but sometimes it doesn't.

Pulled off driver side head found #5 full of the big black bird seed, lol. I’ll pull the pistons and run the dingle berry hone then light touch up on valves and new seals. If I can find some cheap rings I’ll throw them in. Wash it good inside, steel shim gaskets, let er rip. Did the 74 346 heads have hardened seats?

i think the 1971 "346" heads where one year only, no on the harden seats as leaded fuel was still being made and sold in 1970, probably until 1976 or maybe even later than that