PontiacBonnevilleClub.com

Hi all,
I've tried searching on here, but web searches look at me like I'm stupid when I input anything series 1. First I'll tell you what I'm planning and maybe yall could point me in the proper direction.
I'm planning on ordering headers for a series1, hack the flanges off and make my own flanges to fit the series 1. I looking for dimensions, specs, etc... for the series 1 supercharged version, or at the very least, thespecs on the heads, e.g. exhaust port dimensions.
As always, any help is appreciated.

If you mean getting Series 2 headers and modifying them to fit a Series 1 with your flanges, it might take more work than you think. Not only is the port sequence different but the S1 has a 1" taller deck height.

I can't remember seeing the external dimensions you're after being posted before.

I've gone the other way with that.

I put the series 2 flange on a 1986 LG3 manifold set. The spacing between the two close ports was the same as the spacing on the series 2, it was one primary on each side that needed to be modified. Then, because of the difference in the deck height, the outlet flange had to move (in my case up) about 3/4" to clear the steering rack. If you're going the other way using series 2 headers you'd probably have to adjust the overall angle on the downpipe section so it clears the tunnel. That would probably be the hardest part of it, because there are 3 primaries and the front header that all have to fit into the tunnel - it's crowded and not much room for error. A couple of angle cuts might be enough to effectively lower them.

As for getting some series 1 flanges, I recommend grabbing a manifold set from one in the junkyard. They are thicker than most weld flanges you can find. That's what I did to build the manifolds on my series 1 truck project. I have yet to see a series 1 header flange anywhere you can buy new. If I had time I would measure out one of the ones I have and post a dimension file up - but the one I have is buried in storage at the moment..