250-500cc engine swap?

I was just thinking could I swap my 2002 wr 250 2 stroke for a 4 stroke engine ? are the frames even the same just wondering

I highly doubt the mounts would line up, let alone the chain line.

What are you trying to accomplish exactly? I'm thinking if you want a fourstroke, you'd be better off selling and buying one. If you want something more tractable, I'd say a flywheel weight would be a good place to start. Followed by a pipe tuned for low end like an FMF gnarly with a long silencer.

I've had a bunch of Husky 4t 450s, no way the engines will fit.

I'm not going to do it i was just thinking has it ever been done before im fine with my 2 stroke

The other way is popular with later model KTMs, new frames and running gear, older 2t or even 4t engines. The 4t requires a bigger cradle to fit so getting a 2t in there isn't much of a problem.