Wouldn't these be the answer to a lot of fitment issues ??

Hedman BB p/n 75066

If you've got the skills, equipment and time on your hands, then yes.

what is the problem w/ off the shelf? If it's a B-body most headers are an easy fit.

Not when you start reading all the footnotes ... flywheel size, starter type, head manufacturers, etc. !!!!

If I go RB in my 65 dart I will have to go with one of those kits & after listening to the multitude of header fitment issues down thru the years that people have had with tailor made headers(ex for tti's and they are not equal length and are $$$) it's gotta be worth a shot & in my case no choice. Someone has a kit of bendable plastic tubing that you bend up to get the length/fitment right on each tube then take it off & copy it with your header tubing and I remember "headers by ed" when they will still in business had dyno results that claimed that equal length tubes were far superior. I'm just gonna take my time & get it right & tacked together then call a welder.