807 Header vs 807 modified Manifold

[BERNIEHUMBER]

HI:
I have a choice and I was wondering about opinions.

Back in the day I put together a "generic" header for the 807.
Made a header plate using the gasket as a template then mig welded on some steel stater cones.
I miged some high end stainless flex to form a base.
It will take some nip and tucking to match it to the S2's clearance space.
OR
I could take an existing 807 header cut it back of the flange and mig a plate or a 4 to 2 to match the rest of the exhaust.
Thoughts....

 

[jbcollier]

Is there an option 3?

Welding cast is difficult.  You need special materials and you need to pre-heat the entire work piece.  It needs to be kept hot as well and then cooled in sand.  Even with all that, it may still crack.

[BERNIEHUMBER]

HI:
I can weld cast using a preheat oxy then mig welding it.
Sometimes I have used fill material with oxy but have done it often enough to not have serious issues.
Not as easy a straight stick but...
There is another style of 807 exhaust header that that does not need major surgery but its not in my possession.
 

[GavinT]

I'm not convinced about the long stainless flex idea. I'm thinking they may be problematic with vibration and would need to be positively located/supported at the collector end.

Agree with JB - welding cast is said to be tricky, but if you're confident, why not try the cut 'n' shut idea and weld on a flange?
That presumes the twin down pipes will then fit. I think I asked this previously, so will they fit?
If not, I suppose the next step is to make new down pipes.

At some point, I reckon most folk come to the conclusion that fabricating the whole thing is the better way to go. It's not a difficult job (I've made several), but is time consuming.

[BERNIEHUMBER]

HI:
Thanks for the get back.
There are a few ideas on the boil.
I have welded cast a few times in the past(10 times or so) without issues.
I might just get 807 manifold version 2 that doesn't need major surgery.
My plan is to have maximum out come from minimum aggravation input.

[abramjp48]

On one of the 807 conversions I did I used the casted exhaust manifold pictured.  It came off a Fuego (?).  It flowed reasonably well and using it was easier than building a tube header.  The only problem was that it interfered with the fame.  I dealt with that by slightly relieving the top frame rail (less than1/2 inch).  It cleared the bottom rail so modification was necessary  I did rebuild the lip on the top frame rail just to be on the safe side.  The car was an S2 T65.

John Abram
74 TCS, 69 S2

[BERNIEHUMBER]

HI John:
Thanks for the get back.
I appreciate that insight as I agree with the building a tube header.
The one problem I am dealing with is a S2 in absentia(stored in a bag in a barn about 1 hour away).
I knew from earlier postings that the casted exhaust had issues but until hearing from you I didn't know how sever.
I am getting a 16TX cast header which by its configuration doesn't have frame or other serious mods necessary.
The S2 is equipped with a Hermes kit (45 side draft plus header) and was rebuilt at 30K now 35K so there wasn't that urgency.
This 807 was pieced together over 15 years so I felt it time to assemble and eventually put on a test bed.
It looks like I have options!

[BERNIEHUMBER]

HI John:
I see that you are still in the possession of that S2.
As they say a pic is worth a 1K worth of words.
I was wondering if you could post a shot or two of that manifold install?
It would truly tell me what I needed to do if I go that route!
Thanks