Never had an issue with. Title/registration still says 4dr. If ever pulled over I guess keep a picture or two of project in glove box to show em was a 4dr... If they ask.
I guess a guy could have inspected also to have title show 2dr but not sure how that would play out if sold down road. Ethically one would want to pass on to others down the road it was converted. Me personally, I leave title as is.
For what it's worth, I sold a 65 Belvedere 4 dr to a local guy two years back. He did the 2 dr conversion. Did a very very nice job on it, detailed the entire engine and undercarriage, all new interior and the body in primer, only to run into problems and had to sell it.
He listed it on eBay. Told me he got a lot of gas from potential buyers, claiming they would have troubles registering in their state(s). No idea how true that may be, or it they were just blowing, but it did slow down the sale. He ended up selling it outside of eBay to a guy in Florida who didn't care a bit about the title saying 4 door.
I've a 64 Dodge 330 that's been converted, and haven't been concerned about the title situation. I'll do it again down the road I'm sure.
