They came out in 53, jumped to 270 cubes in 55 or 56 and jumped again to 315 and 325 in 57/58. Bob Walker at http://www.hothemiheads.com is the go to guy on early Hemi's. I've used a lot of his stuff on my 392 Hemi engine rebuild (but no personal experience with the 241)
The 241 is the "Red Ram". The bellhousing is made onto the rear of the block. There are better hemis to spend your hard earned money on. I had one. Dont now.
Small Block