400 big block + my 71 Demon

the problem with those headers, they most likely will not fit without giving them a beating with some kind of hammer. usually you will need to heat them up to get a nice clean dent. the ceramic coating is going to look like crap when done and get all rusty. if you want to try the cheap headers go bare, get them to fit, then have them coated. i cant say id want to spend 400$ on "cheap" headers. the flanges are usually thin and warp, thin tubing too. sometimes awful welds on the flanges that dont seal. at least if you go uncoated you can fix or modify them.