2001 Honda prelude, 222k miles. Been using conventional high mileage oil, should it switch to synthetic?

Base model, H22… The H's are notorious for burning oil. Honda MoCo is nonplussed. But I'm still surprised how dark the oil is after only 1000 miles.

Does a 1500-2000 mile oil change cycle make sense. Should it go synthetic.

What are your thoughts to keep it going strong past 300k?

Synthetic has more benefit in a long run vs conventional. Synthetic oil can go beyond 7.5k without changing an oil but still go with the manufacturer suggested.

Its normal for oil to go dark. You never go wrong with fully synthetic 2000.mile oil change is nonsense. Now most big manufacturers in europe are opting for every two years… Or 19000 miles… My renault vans are every 24.000 miles… And no they last as long as your daft every two thousand miles

If you want it to keep "going strong" past 300k, get the engine rebuilt.

The oil is getting dark quickly because of Blowby. That's where combustion gases get past the rings into the sump or crankcase. Either the rings are worn or the cylinder is scratched or scored. You can try Restore engine treatment or others that help reduce blowby. Your best bet would be to run Synthetic Blend. But conventional is fine if you change it often. 3K changes are good. A Full synthetic is more slippery and may make your blowby worse. And it's certainly too expensive to change often. But dark oil that isn't old doesn't mean it's bad, it just has soot in it like a diesel. You could try changing the Filter 1/2 way thru your change schedule. Use Wix or Bosch or other Quality filter, pay at least $8 for it.

I use Valvoline High Mileage oil and change it every 3,000 miles. My oil is still caramel colored when I change it. Your motor oil wasn't changed soon enough or you didn't keep the oil level topped up between oil changes and that cause the oil to break down and get black. Bearings wear out faster when that happens.