gtpvette

iTrader: (2)

Hey Guys,,,
Well it looks like the header project is about to start and I have a couple of quick questions.

First, The what is the hole size (tubing size) on the GM Exahust Flange, part number 12480130?? I'd like to use 1 5/8 tube.

Second,, how are you cutting the tubes?? I have a abrasive chop saw,,, but it's a bit of a pain. I looked into band saw but space in the garage is an issue. Read about autozone exahust tube cutter. WHat's the trick setup for nice stright cuts???

Lastly,,,, what gauge tube are you using,, 18 or 16??

Thanks!

Skele4door

iTrader: (1)

The GM flanges have 1 5/8" outlets. A band saw would certinaly make cuts easier, but you should be fine with a chop saw. Just take your time and make sure you don't lose any fingies or tosies

BTW, someone posted a link to this place in another forum and they sell mandrel bends dirt cheap.

http://store.racing-solutions.org/hebukit1.html

Quick Double Nickel

iTrader: (5)

Does GM make a header flange for 1 3/4" tubing. If so, what's the part number on that?

Skele4door

iTrader: (1)

I've only seen the 1 5/8" flange from GM, but you could probably call them and ask. I think I've seen 1 3/4" flanges around from Burns or Hooker or something, but they were pretty pricey.

Mr. Hyde

iTrader: (10)

GM does make the 1 3/4" flanges, I bought them at my local GM dealer parts counter. $20 a side, basically.

eagleuh1

My GMPP header flanges were 13/4", I think $37 for set. Real thick flange too. Ordered over the internet.

jannes_z-28

I would say that the GM #12480130 is suitable for both 1 3/4 and 1 5/8.

The holes in the flange will let you stick the 1 3/4 tube in the hole and weld it on the "inside"

The 1 5/8s will match the hole but you have to weld on the "outside".

As for cutting I used a plain hacksaw, just be careful and you can cut it straght. I mark the tube all the way for the cut and then follow it with the saw. Important to have fresh blades.

Bandsaw would be the best but for one job it would be overkill to buy one.

Jan

eagleuh1

Huh? The 13/4 flange, the 13/4 header tube fit right in the hole. 15/8 is a smaller tube, won't even touch the sides of the flange hole. You might be able to get it roled to spread the tube out at the end to match the end of the tube to the inside of the 13/4 hole, kind of a step in the tube diameter.

Quick Double Nickel

iTrader: (5)

Is there a separate part # for the 1-3/4" flanges by chance?

eagleuh1

The above mentioned part #12480130, at http://www.gmgoodwrench.com. This is what I have. The hole on the flanges I recieved were 13/4".

LS1-IROC

iTrader: (4)

If you don't have a bandsaw, the next best thing I have used is a 4 inch cut-off wheel on a right angle grinder. Works well. Also helps if you put tape around the tube for a guide.