Where's the best place to get 1 5/8" or 1 3/4" mild steel mandrel u-bends in a 14 gauge? It seems that no one carries the stuff. Also, where can I pick up a set of 3/8" or even 1/2" sbc header flanges for this project?

 

you should be able to purchase or find out anything you need from this Web Link

http://www.burnsstainless.com/index.htm

they handle mostly Stainless tubing , but with their connections/knowledge should be able to point you to source of tubing you want , just Email or call them

 

http://www.headersbyed.com/

 

You are corect that 14 ga. bends, especially in primary pipe sizes are dificult to find. Are they for turbo headers? If so, I'm assuming you want the .083 wall for strength (mounting the turbo?) heat retention and durability as well as cost and fabrication ease. 16 ga 304 stainless should be fairly strong and durable (compared to mild steel), and if coated should retain the heat.

From what I can find, 14 ga. mild steel mandrel bends are pretty much "unobtanium".

 

You aren't kidding about that stuff being hard to find. Anyhow, after talking with a few people who know alot more about turbos that I do, I'm just going to use a set of short headers and not bother with building my own. Since it's a street vehicle and the headers are going to be at a fatigue point like once in a blue moon, they should be alright. And if they do fatigue, they're only like $125 to replace them. Also, we're going to make some plates out of 1/4" steel to help support everything.