Eldorado Header

[Perry G]

I have had an on going problem with the manifold on my 78 and my 76 Eldorado. I know I'm not the only one thats had this problem and it's getting very hard on the wallet to keep replacing a part thats getting harder to find, And you know will fail again.
My question is,, Is there a header out there that will work without building one myself ?  If someone has built a header for there ride I would like to get some info on how they went about it.
  I have done a search on this and haven't seen anything that applies to what I want to do. Any help on this would be just MINT.

[35-709]

Talk to Marty at MTS (Maximum Torque Specialties), they specialize in 472/500/425 Cadillac engines and have headers for them ---- http://www.mtscadparts.com/MTSHome.htm
Technical Contact:   Marty@MTScadparts.com
Phone: (760) 247-2533   
13641 John Glenn Rd #B
Apple Valley, CA 92308

I have been disagreed with on this point before, but even though the factory built these engines without gaskets between the block and the exhaust manifold (when the were clean and perfectly flush to each other), if you remove/replace the stock exhaust manifolds you should always use a gasket (NAPA, etc.).  This is not MY idea but the advice of my engine builder, FWIW.  Those manifolds can be repaired by a competent welder ---- been there done that on a '66 Caddy and others.  Good luck.
 

[Perry G]

Thanks Geoff. I welded up the manifold on my 76 last year. Worked out good till the port in front of that one broke. Thats when I replaced it. Has anyone had any luck with a quick fix thats lasted any amount of time?

[Joe G 12138]

All the left hand manifolds seem to break in the same place....starting at the mounting bolt hole as shown in the picture. I've had good luck by doing three things with the replacement or repaired part. First......drill the mounting holes larger than the factory size.  Second.....use the gaskets!     Third....coat both sides of the gasket with a mix of High temperature Teflon pipe sealing compound and dry graphite. These three things allow movement during heating/cooling cycles. When there's expansion, somethings got to give, and the manifold cracks if it is locked in place, especially by the bolts and tight hole situation. The mix of pipe sealant may smoke a little at first, but it's really just a carrier to hold the dry graphit in place. Good luck!

[35-709]

Dern good advice!  IMHO.

[Bob Hoffmann CLC#96]

Those manifolds only break on the cars with the heat shields on them. I've never seen a 68 manifold crack. They don't have shields. Those manifolds are available from several sources as reproductions. Headers always seem to be a PITA. HTH, Bob

[Perry G]

Thanks for the advice guys,,  I have only had problems with the drivers side on these. As far as the heat shield,, I never thought of that, Its so true. I'm going to do a temp fix on this thing for now. I'm going to pull the convert in the shop and make up a set of headers for that one,No front clip on that one. Install them on the 78 and make a new set for the 76. Should be good at making the headers look good by that time. Will let you know how it all turns out. Thanks again guys

[Glen]

Talk to Marty at MTS (Maximum Torque Specialties), they specialize in 472/500/425 Cadillac engines and have headers for them ---- http://www.mtscadparts.com/MTSHome.htm
Technical Contact:   Marty@MTScadparts.com
Phone: (760) 247-2533   
13641 John Glenn Rd #B
Apple Valley, CA 92308

I have been disagreed with on this point before, but even though the factory built these engines without gaskets between the block and the exhaust manifold (when the were clean and perfectly flush to each other), if you remove/replace the stock exhaust manifolds you should always use a gasket (NAPA, etc.).  This is not MY idea but the advice of my engine builder, FWIW.  Those manifolds can be repaired by a competent welder ---- been there done that on a '66 Caddy and others.  Good luck.
 

I have one thing to add to Geoff’s comment. Do not over torque the manifold bolts.  As he says the manifold has to expand and contract at a different rate than the head it is bolted to, so it must be able to slide on the head.  IIRC the torque for the manifold bolts are only about 30 ft-lb.  Most mechanics like to torque it down much more than that to prevent leaks. 

I’ve never had to use the gaskets but if you can not get a seal with the proper torque then you need to use the gaskets.

Glen