Is there a physical difference between these HP exhaust manifolds?

[Dino]

440   1968-69   440 Magnum / Right   2806900
440   1970-71   B - C Body / Right   2899879

I know the heat riser is different but are they pretty much the same cast?  Is the part going to the pipes different?  Just trying to figure out which one to get.  I have a '71 440 in a '69.

My driver side manifold is this one:
440   1970-71   B - C Body / Left   2951865

[Nacho-RT74]

sometimes the diff is just the indexing on flange holes

sometimes is also the flange angle

sometimes is the flange location itself.

LOOOONG tiome ago year One got a nice tech archive showing these differences, when they began to offer the repro manifolds... dunno if still ( long time since last time I visited year one website )

[71 SE3834V]

Do you have pics to compare?
Buy 'em both and sell the one you don't use for big bucks! See how easy it is to spend other peoples money? Mine is the 879 if you need to see one in person.

[Dino]

I've got a lead on a 900 for a good price.  It no longer has the heat riser but I can live with that.  It would probably be a bad idea to use it anyway.  If I get it I'd love to compare it to yours.   

[Dino]

I just bought the 900.  The only part of the heat riser still there is the shaft going through the manifold.  The inner disc itself is gone.  I wonder if I can find the counter weight for a good price and just mount it for look?

Now I have to figure out if the driver side is a good match.  If the flange angle is different then I should probably sell it and get one for a '69.  Or trade for one.

[RallyeMike]

Pretty sure Nacho nailed it. The indexing of the outlet flange bolts is the difference.

[71 SE3834V]

I've got a lead on a 900 for a good price.  It no longer has the heat riser but I can live with that.  It would probably be a bad idea to use it anyway.  If I get it I'd love to compare it to yours.   

Might be kinda hard with on the car but I have one decent picture.

I just bought the 900.  The only part of the heat riser still there is the shaft going through the manifold.  The inner disc itself is gone.  I wonder if I can find the counter weight for a good price and just mount it for look?

Now I have to figure out if the driver side is a good match.  If the flange angle is different then I should probably sell it and get one for a '69.  Or trade for one.

I suppose I could part with the heat riser parts that are sitting on my shelf. Don't think they'll ever see the light of day again.

[Dino]

Yep I think Nacho got it right.  I can't find any real comparison yet but I'll keep looking.

Thanks Jeff but your heat riser parts won't fit this one.  The weight is on the side and on yours it should be on the front.  Thanks for the offer though!   

This is what the weight on mine would be like.

[71 SE3834V]

Oh yeah. That looks like the one we saw at the swap meet.

Looking at the pic I would say the mounting holes for the flange are at about 4 o'clock & 10 o'clock looking at it from the end while laying flat whereas mine is at about 2 & 8 o'clock.