looking for fabrication ideas

[benno505]

i am building an aluminium sheetmetal intake manifold for a slant 6 and was wondergin if anyone had any ideas of transitioning the runners from round tube to square for the square intake ports.
this is a home build and do not have alot of access to proper forming dies etc.

[Motorcitydak]

I just built this for my intake elbow, I had to make it compact for packaging. Maybe it can help you a little. It is made from steel which was easier to work with (from a welding stand point) but sheet is sheet so anything is possible and if it gets bent wrong just grab a new piece

[raustinss]

Aluminum is like butter, if it's just the corners that your concerned about you can do a few things....
1 find the center lines of the square intake ports...height divided by two and same with the width...mark them then measure the outer diameter of the round tubing divide that into 4 and mark it, now your goal is to make the marks all match. You probably will need to squeeze the tubing width which obviously will make it more oval like once the tubing is skinny enough to fit to the size of the square intake port.....tack weld the sides. Now you will either need to heat the aluminum and try to stretch it to fit or you will have to cut the tubing then open the cut up to make the tubing reach the top and bottom of the square opening. Tack weld. Now if possible bolt the whole thing to the car and make sure everything fits and they're aren't any interface issues. If everything is good then it's time to finish welding try to weld it attached to the head to help prevent warping. You will want to weld the round tubing to the square flange first so your tacks don't break, then go back and weld the cuts closed this might take a piece of copper or steel as a backer. Once everything is closed up make sure to weld the inside perimeter of the square flange and then it's time to grind everything smooth and clean
Good luck

[benno505]

thanks guys, Raustiss, this was the approach i was going to take, thanks

[raustinss]

No problem, if possible toss a few pictures up when done would like to see how you made out. If you need any further help I'm available just email me.
Good luck