usually mandrel-bends.com.
http://www.stainlessheaders.com/flanges for the flanges which are $150 for a pair. Total is about $583 for all materials.
[TABLE="width: 100%"]
<tbody>[TR]
[TD][TABLE="class: productListing, width: 100%"]
<tbody>[TR]
[TD="class: productListing-heading, bgcolor: #CCCCCC, align: center"]Remove[/TD]
[TD="class: productListing-heading, bgcolor: #CCCCCC"]Product(s)[/TD]
[TD="class: productListing-heading, bgcolor: #CCCCCC, align: center"]Qty.[/TD]
[TD="class: productListing-heading, bgcolor: #CCCCCC, align: right"]Price Per.[/TD]
[TD="class: productListing-heading, bgcolor: #CCCCCC, align: right"]Total[/TD]
[/TR]
[TR="class: productListing-even"]
[TD="class: productListing-data, align: center"]<input type="checkbox" name="cart_delete[]" value="531">[/TD]
[TD="class: productListing-data"]
[/TD]
[TD="class: productListing-data, align: center"]<input type="text" name="cart_quantity[]" value="10" size="4" maxlength="4">[/TD]
[TD="class: productListing-data, align: right"]
$19.50[/TD]
[TD="class: productListing-data, align: right"]
$195.00[/TD]
[/TR]
[TR="class: productListing-odd, bgcolor: #F1F1F1"]
[TD="class: productListing-data, align: center"]<input type="checkbox" name="cart_delete[]" value="2804">[/TD]
[TD="class: productListing-data"]
[/TD]
[TD="class: productListing-data, align: center"]<input type="text" name="cart_quantity[]" value="1" size="4" maxlength="4">[/TD]
[TD="class: productListing-data, align: right"]
$168.10[/TD]
[TD="class: productListing-data, align: right"]
$168.10[/TD]
[/TR]
[TR="class: productListing-even"]
[TD="class: productListing-data, align: center"]<input type="checkbox" name="cart_delete[]" value="779">[/TD]
[TD="class: productListing-data"]
[/TD]
[TD="class: productListing-data, align: center"]<input type="text" name="cart_quantity[]" value="2" size="4" maxlength="4">[/TD]
[TD="class: productListing-data, align: right"]
$34.99[/TD]
[TD="class: productListing-data, align: right"]
$69.98[/TD]
[/TR]
</tbody>[/TABLE]
[/TD]
[/TR]
[TR]
[TD]
[/TD]
[/TR]
[TR]
[TD="class: main, bgcolor: inherit, align: right"]
Total: $433.08[/TD]
[/TR]
</tbody>[/TABLE]
IDK where you are buying material. But that alone was a thousand bucks for me. That means the guy making them must work for $8/hr, for $1,400.