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cunningplan
29-11-07, 08:08 AM
Been asked to get some headers made, got a mate who does stainless steel exhausts and the car owner got the flanges sent straight to me, but which is up?? as the holes are offset.

http://usera.imagecave.com/cunningplan/2007_1128Image0016.JPG

This way shown in the photo?

Dont want to get them made and find they are unside down when fitted.

Thanks in advance for your help
langysrodshop
29-11-07, 09:38 AM
Bolt them on to a head ???
Adam
29-11-07, 01:57 PM
Is that Colins exhaust Tony? I'll pop down in a minute and look at a gasket.

http://static.summitracing.com/global/images/prod/large/big-11108.jpg

Seems the bolts are directly in line with the ports on the flanges when fitted to the engine but I will check in a while mate.
Paul B
29-11-07, 02:16 PM
Been asked to get some headers made, got a mate who does stainless steel exhausts and the car owner got the flanges sent straight to me, but which is up?? as the holes are offset.


This way shown in the photo?

Dont want to get them made and find they are unside down when fitted.

Thanks in advance for your help
Put them against a cylinbder head, see which lines up best. Surely you'll have to do that to get the headers made, to make sure they line up and fit around the motor?
Paul G
29-11-07, 04:00 PM
Bolts are below port centre I believe , unless I drew it upside down !
Adam
29-11-07, 04:18 PM
Tony
I have just had a look at 3 small block Chevy engines (inc Colins) and one set of headers. The bolt holes seem to be centre of the port.
langysrodshop
29-11-07, 04:20 PM
That's what i thought ???



Tony
I have just had a look at 3 small block Chevy engines (inc Colins) and one set of headers. The bolt holes seem to be centre of the port.
rem
29-11-07, 08:48 PM
That's what i thought ???

That's what I thought too, which is why more than a few cars have been seen with them fitted upside down, drag-boat / rat rod stylee.

Not Mopar ones are they? 383/etc. have a similar port config.?
cunningplan
29-11-07, 10:06 PM
yes Adam, Thay are Colin's.
All we have down here is one old header from the race car, you would think I could match the old flanges, BUT these are diffrent from the new ones, so we cant do that.
Looking at your photos, if you look you can see the extra bits for the inner holes on the underside, so they must be delow the center line and the one in my photo upside down.
Thanks for you help
Tony
cunningplan
29-11-07, 10:12 PM
Not Mopar ones are they? 383/etc. have a similar port config.?

when got the new ones and we found they were not the same, I tried the old and the new on one of my spare 360 heads.
cunningplan
29-11-07, 10:17 PM
Put them against a cylinbder head, see which lines up best. Surely you'll have to do that to get the headers made, to make sure they line up and fit around the motor?


They are from a old race car, as Adam said, he has the motor, Colin has the car and one header is down with me.

We are going to bolt the old one to something solid and copy that, but as each side is different, its not going to be easy.
Adam
30-11-07, 03:22 PM
Tony, Colin's engine is done now. Do you want me to send you a pic of the head ports. The bolt holes are definately in the centre. I have mocked up my patriot headers to it and they fit ok.

If you had to decide I would have the ports so they sit on the slightly higher side as more flow is generated at the top of the exhaust port than the bottom. Or you could elongate the mounting holes slightly. A lot of header companies do this anyway to 'guarantee' that their products fit! Exhaust gaskets have elongated bolt holes for the same reason.
cunningplan
30-11-07, 05:34 PM
Tony, Colin's engine is done now. Do you want me to send you a pic of the head ports. The bolt holes are definately in the centre. I have mocked up my patriot headers to it and they fit ok.

.

Yes if you could Adam, we hope to do them one eveing next week.

Tony
rem
30-11-07, 05:42 PM
If it is a race car, I would argue that the headers need to match the ports (or at least be sure not to obscure them), so why not trace the heads on a piece of paper and post them?
Adam
30-11-07, 08:06 PM
If it is a race car, I would argue that the headers need to match the ports (or at least be sure not to obscure them), so why not trace the heads on a piece of paper and post them?


I think Tony just wants to get them right for making the headers. The flanges are already done and look thick enough to port should Colin want to at a later date. This engine is just a temp re-ring stand in till the car is fully completed. Hopefully some ally heads will find their way on to it and then everything can be port matched.