Need exhaust manifold kit, '66 Eldo

[Christian Millman]

Hi all,

I'm having a dickens of a time finding new exhaust manifolds for my '66 Eldorado. It has the original 429 V8. I've tried all my regular sources, including NAPA and several specialty suppliers, all with no luck. Has anyone found a good source for manifolds?

Thanks kindly.

Christian Millman CLC# 23152

[John Morris #23947]

A hundred eons may pass and I don't believe you will ever find new ones.

[35-709]

I have not heard of new ones available from ANY source either.  If yours are cracked they can be welded by a competent welder.  You can also find good used ones out there.  My advice is to use exhaust manifold gaskets when you reassemble the manifolds to the engine.

[Christian Millman]

Thanks for the replies, gents. You're right. New ones are an impossibility. And I have put in new manifold gaskets but I'm still leaking exhaust (and noise) which isn't so much fun because it's right by the air intake. Which is fine unless I put the roof up. I did find out you can get used manifolds that are magnafluxed, glass beaded, resurfaced and painted at Cadillacs Only. Has anyone had any experience with these? They're not cheap so it'd be good to find out what the list thinks.

Thanks again.

Christian Millman CLC# 23152

[35-709]

You may not have an exhaust manifold leak at all, but could very well have an exhaust leak at the intake manifold if you are hearing it "by the air intake".  Exhaust goes from the right side of the intake manifold to the other side under the carb when the engine is cold and the exhaust heat riser valve is closed.  It is common for the riser to stick closed forcing hot exhaust through that area at all times which in time can crack the intake manifold (check for that) causing an exhaust leak, or destroying the intake gasket on either or both sides where the exhaust passes through there also creating an exhaust leak.  If a bad gasket is left unattended the exhaust will erode the metal on the intake as well as the engine block making it hard to seal that area even after planing the intake.  This is a common occurrence on the 390's and 429's I have played with. 
In my opinion, unless you use the car in very cold weather or insist on originality, I would get rid of the troublesome heat riser (Heat Control Valve as the shop manual calls it) by gutting it and plugging the shaft hole and reinstalling it with 2 new gaskets, or just block or wire it open.  Otherwise make sure it is loose and working properly --- PB Blaster does well --- and check to make sure it is operating properly OFTEN --- after you fix your problem.  Keeping a close eye on the heat riser's proper operation is a good practice even if it is not your problem here.