I need to replace the fuel tank sending unit on my '70 Charger. I have read many posts that the remanufactured units are notoriously inaccurate. Can anyone recommend a replacement unit that they had a good experience with and works as it should?

I wish I could but I only had bad experience with Spectra. Didn't read accurately. I'd search for a NOS and buy one if not too unreasonably priced. If Vans Auto makes one for your car they usually have some good stuff. Maybe someone will have some feedback for you.

https://vansauto.com/product-category/fuel-tank-sending-units-and-related/sending-units/

My son has bought 3-4 of them for various old mopars, all aftermarket, all from the same place/ all have been junk.
He is re replacing the most recent one, got real lucky at the last swap we went to, a guy had 2 NOS ones for his application.
(This one's a 72 C body wagon) I shoulda bought em both
The seller did say that he's sold a few to guys who cut the tube and modified it to fit their application, at least that way they got new electrical guts

I got the stainless 3/8 one for my 65 from Ebay like 10 years ago.Its pretty accurate.Its probally as good as the factory OE one was.

There is a way out if you have a inaccurate sending unit.
Tanks Inc. has a tuning tool called meter match.
It's a electronic devise that let's you to tune your sending unit
to your gas gauge.
I installed one last year.

Mike

WHAT HE SAID!!!!
The issue is across all car lines and suppliers (GM, Ford etc.) Owning a shop, we have spent HOURS draining, adjusting and refilling to wind up with a gauge that is inaccurate on the to full or empty side is a frustrating PITA. BTDT way more times than I can count. I don't know why it is so flipping hard to make one that is correct but it likely has to do with $$$ or laziness. Spectre several years back said they were going to resolve the issue but failed to do any better.
I now install it, check accuracy and if it's off (always is), implement the above solution and my hair has grown back. FYI, Tanks is a good company and will claim no problems with their SU but I know from experience that's 💩💩💩

With the meter match the fuel read will be way more accurate throughout the whole gauge sweep. Way better than the factory ever was. Plus the are some options on setting it up and it also allows you to run a low fuel warning light.

I bought one from Kramer Auto about 5 yrs ago and still reads accurate.
http://www.kramerauto.com

Why should we have to buy a 2nd tag a long component to make haphazard aftermarket stuff work? The one in the 80 d150 and the 87 ramcharger still have 1/2 tank when they read empty, the one he bought for the 72 fury shows nothing at all. Pure junk
There used to be companies that advertised a service where the rebuilt original sending units, always wanted to try one of those places but lost the contact info that I had for one in Ohio

The last Spectra tank I got for a 69 Charger was not even close to the right ohms reading.

because what is being offered is as you stated

Quote

Pure junk

. In my experiences (MANY) one can spend days trying to get a somewhat accurate reading at full AND empty. I found that one usually could get one or the other (full/empty) but not both. So, I would usually settle on an empty reading (with a little reserve), and 3/4 to 7/8 reading when full.
The Tanks add on device corrects this issue. I agree we shouldn't have to resort to doing so but.
1. It is the result of people like myself wanting to retire.
2. The younger generation not interested in taking a business over.
3. Our money grubbing CEO's putting profit over quality, (Gotta have that 2nd hose on the lake AND keep for the mistress happy).
4. The NAFTA by Reagan in the 80's, followed up by Cliton opening the door to China in 2000.
5. The consumers demanding lower prices while workers demanded higher wages.

NAFTA? The 80's?? Try 1993.

Nafta didn't get signed till 1993 and it wasn't till after that signing it started affecting things. Don't lay this one on Reagan.

I bought a Spectra Premium FG67A and the resistance sweep was about 10 - 80 ohms. It is off by around 1/8 tank on the gauge, there's more fuel than shown, I can live with that, maybe some day I'll play around with bending the float arm for better accuracy. This forum did teach me a mod to add a ground wire which I did. I have two YouTube videos (before and after) of an A-body sending unit I fixed for a friend with that modifications. The picture was taken from Moparts,