I've been looking for headers to put on my Cutlass Supreme. I have a 455 in it and I am having a tough time finding them. It seems like they list them up to 1969 then go from 71 up. What is the big difference?

 

There is no difference. Any header that fits a 69 or 71 will fit a 70.

Where were you seeing this information?

 

This BS again.....

Someone, somewhere decided that a Cutlass Supreme was different in some strange way so the "except supreme" footnote started showing up in header catalogs many moons ago and never left even though is has been PROVEN time and time again that there is no difference in the cars. They use the same frame and the bodies are the same from the B pillar forward.
So pay no mind to those notations and just buy you a good set of BBO headers for you car and run with it. Just keep in mind that relocation the proportioning valve to the top of the frame may be in order, so plan for that.

 

I just pulled a set out of a 72 I am parting out.
$50.00 plus the ride

 

I just installed a set of Doug's headers in a '71 455 and was NOT happy with the fittment especially since one header was much lower than the other one.

 

I prefer manifolds myself

 

So you dislike performance. Cool.

 

I had the same issue with Doug's headers. One side was literally hitting the floor. ARH few of us had some some serious issues with fitment as well. I posted about both of these somewhere on here.
So far the only headers I haven't any complaints about are Dick Miller's.

 

20 years ago when I put a 455 in a 70 Cutlass S I bought Flowtech headers and had no issues with fitment. I don't recall how close the drivers side was the the distribution block, but I know I didn't have to ding anything to get them in.
My only problem was my front springs were SHOT and I bottomed them out quite often because of it and ended up with flat bottomed collectors.

 

It seems like everybody's quality and QC went to crap last few years. I had 2 sets of hooker headers, same part number one set from early 2000 and one brand new and brand new set wouldn't fit right.
ARH, I have heard nothing but good stuff, but seems like everybody that bought them around the same the I did had problems. Same thing with Doug's, people that bought the 5-6 years ago say they fit perfect, if you bought the last 2 years they fit like crap.

 

I bought a pair of Flowtech headers for 455 in a 1970 Cutlass and they fit perfectly...bought them from a fellow CO member

 

Cheap isn't always a bad thing.