Modify Your Stock Intercooler

You'll also see some benefit by removing the gasket along the firewall at the rear of the hood and adding an intercooler scoop extension since this both directs more air through the ICs fins but it also lets more air out of the engine compartment reducing the high pressure buildup. (If you've ever been in a GN with a fiberglas hood at 100 mph, you've probably noticed how the hood bows up.)

Cutting Your Own Neck:

The minimum tools required are a hacksaw and some type of HD sander with a 24 or 36 grit disk or belt. You also need some body filler, spot repair putty, primer, semi-gloss black paint and somebody to weld it. My friend owns a Heliarc & charges $25 each for ours.

I use a fixture that I built which mocks up the location of the IC inlet and outlet. This is for determining when the intercooler is ready for having the neck welded on but thanks to a method used by David Chase, a member of the TurboBuick.com bulletin board, the following method works very well in lieu of a fixture.

First lay the IC on cardboard and trace lines along the edges, bottom and top. These are your reference points that will allow you to reposition it in exactly the same spot while test fitting the new neck. Next, draw a circle around the stock neck while it rests on the cardboard. To orient the new neck, you'll need to draw a larger, concentric circle around the smaller one. Now you're ready to cut. To locate the cut line, compare the large neck against the IC & mark it about 1/2" above where it looks like it needs to be cut. Remember to compare the centerline of the outlets. Saw the neck off then lay the IC back on the cardboard and position the Duttweiler neck, comparing the neck inlet with the circle. Sanding the IC to acheive your fit is preferred since the inside diameter would decrease if you shortened the neck. If you remove too much material creating a gap after the sanding is complete, the welder can easily fill it in. You'll see that the outside of the neck doesn't match the outside contour of the IC, so body filler will need to be used to blend things together. There also will be a slight mismatch on the inside. To correct this and to improve airflow, taper the inside of the IC with a file and align the edges opposite the turbo to avoid a ledge there. When done fitting up, scribe marks on the sides of the two parts for reference. Have the welder tack a corner in place and check the marks before proceeding. With a corner tacked on, view the IC from several angles & particularly from above to see if the new neck aligns squarely. Make sure that the neck opening is parallel with the edge of the IC tank. After welding, you can grind down the beads a little & blend the joint with body filler. Next is a trip to the carwash to get the dust, etc out and it's ready for painting.

Necks are available from Kirban Performance for $68.95 (See the link below.)

Returning your intercooler back to original condition is possible too. Let me know if I can be of help.

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