It was economical for me. $5.00 for the elbow, flange and blockoff plates were scrap laying around and a bottle of rye for the welder. Just take the time to fit it so the flow is smooth and prep nice bevels with 1/16" lands for the welder. Procedure for steel pipe to cast manifold was preheat to 400 deg., use UTP FN85 cast rod, peen short welds in between passes, and cool slow with blanket, sand, etc. I should have taken more pictures after welding. This is all I've got:

http://s176.photobucket.com/albums/w186/curt160/exhaust/?action=view&current=000_0020.jpg

As for a hole I think any method that allows the 2 sides to mix "pollutes" the cackle it makes.

1952 1300 Canadian 1/2 ton restomod
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