L-Series, 4 cylinder, Exhaust Downpipe Flange
I've had these made for a long time. I'm no longer going to have them made to sell. They don't move fast enough to bother with, so I figured I'd share the CAD files for them on GrabCAD.com
I'll share the pdf here. You can print it out 1:1 and use it as a template to make your own out of 3/8" plate steel. If you want to plasma or laser cut them, go to grabcad to get the dxf file. SendCutSend.com can cut and ship 1 or 2 of these for about $29, but you can order 3 of them for about $38. They have a $29 minimum which is what causes the first two to be the same price.
They should fit the L16, L18, and L20B exhaust manifolds.