Hello, new here with a 70 challenger
 

Im looking for info on a 5.7 hemi swap into a 70 challenger! Has anyone here done this?

welcome to the site, i dont know if anyone here has done the swap but
i have been sitting on this article for future reference so maybe it can help
you out.
Hemi Engine Swap Guide - 5.7L and 6.1L Hemis For Early Mopars - Car Craft Magazine

Actually, this swap has been done numerous times and you should be able to find information by doing a search on line. There are even companies offering plug in wire harnesses for this swap. Just be sure and do your homework...before starting, as bolting in the engine is just the starting point and there is a lot more that goes into an engine swap such as this.......

By the way, just to add my two cents....if you own an RT or even a really nice 318 Challenger from 1970, you may want to rethink doing this type of swap as an original will be worth more in the long run. And, used "new" Challengers will become cheaper as the years go by making them more attractive for those wanting a Challenger with the new HEMI engine. (Again, just my two cents)