Thanks for the above input and I have made an additional post in the STREET section (for those who may have not seen it) clarifying my original intent.

According to this, http://forums.y-blocksforever.com/FindPost99031.aspx they are marginally better than the '57 manifolds and that probably makes sense, given the more elegant design.


Lawrenceville, GA

Lanny.  I've posted the pictures you sent me of the Fenton manifolds you have for sale. For those looking at these, I think the application for these is Ford passenger car. My read on this is based upon the location of the rear mounting bolt on the driver's side.  The '55-'57 'Birds' rear exhaust manifold bolt, the one closest to the firewall, is accessible before the manifold turns down. On the passenger car exhaust manifolds, the rear bolt is only accessible beyond where the manifold turns down.
Additionally, to help Forum members who might be interested, in Lanny's reply to me when sending the pictures he stated, "they are not new, have surface rust and would clean up nicely with blasting, the mating surfaces are level with a a good straight-edge, there are no visible cracks, and no repairs are needed."










I was interested in these for their period uniqueness rather than for their possible performance value in assembling a car.
Again, I don't believe Lanny's manifolds will fit a '55, '56, or '57 'Bird.
I think they'd make a GreaT conversation piece!  Hope this helps anyone interested.    


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

As far as I’m aware, Fenton only made one version of the exhaust manifolds for the Ford Y.  I tried looking in some of my older catalogues going back to 1966 but no Fenton listings.
 
While the terms ‘headers’ and ‘manifolds’ are technically interchangeable, in the automotive world the term ‘headers’ typically denote tubing construction while ‘manifolds’ denote cast iron construction.  Here are pictures of the various Ford and Fenton exhaust manifolds for the Ford Y.
   

   

Lorena, Texas (South of Waco)

No, we are not talking about manifolds.  They are original cast iron FENTON headers, as the ones pictured.  They are factory stamped with the part numbers as shown in my original post, undoubtedly to show proper fitment.  I have been unable to find any old Fenton literature showing part numbers on any of the older speed equipment and hoped that some of you old hotrodders may shed some light.

I'm assuming we are talking exhaust manifolds rather than headers.  Do they look anything like these? As mentioned, picture(s) would help.

Lorena, Texas (South of Waco)

If you could post a picture, that would help. I can't tell you anything from the numbers you provided. If they are long tube headers, they are most likely for a truck or they could be fenderwell headers. 

  Ron Lane,  Meridian, ID

I have an original set of y-block Fenton headers, numbers RH0708 and LH0708, that I have had for over 40 years.  Can anyone decode the part number for fitment, i.e. cid and year?