Paragon Repoduction Exhaust Manifold

[Clark K.]

Does anyone know whether the reproduction (GM #3846563) left-side exhaust manifold that Paragon sells is a dead ringer for an original?

I talked to someone at Paragon today about the correctness of their L76 exhaust manifolds. The guy told me that they use the original tooling and make them "in house". When asked whether the Paragon repros had the typical repro grinding marks on the top surface, he told me that this particular manifold is usually not ground down since there is no "flash" at the top of these units.

The other manifolds they make have what he considers dangerously sharp flash left after the part is made, requiring them to grind down the flashing before sending it out to an unsuspecting customer.

I am trying to decide on a used original ($$$) or the Paragon reproduction ($250) to replace my left-side exhaust manifold on my 1965 with L76 (327/365hp) engine. The current manifold has been "cherried up" by a former owner, causing a 3 point originality deduction at flight judging meets.
-Clark

[Bruce B.]

Re: Paragon Repoduction Exhaust Manifold

I don't know anything about the exhaust manifold but the statement that they make them "in house" makes me question the part.
I don't think Paragon has a foundry which could cast an exhaust manifold.
Am I wrong??

[Ridge K.]

Re: Paragon Repoduction Exhaust Manifold

Bruce makes an excellent point. Perhaps the Paragon representative was just using a figure of speech.

It would be highly unlikely that Paragon has a blast furnace capable of melting iron (2800+ degrees). Highly unlikely....

[Tracy C.]

Re: Paragon Repoduction Exhaust Manifold

Clark,

The repops I've seen have 4 longer flash nubs instead of the 8 short ones. See if the vendor will send a pic of the top of the manifold to you.

tc

[Joe L.]

Re: Paragon Repoduction Exhaust Manifold

Bruce makes an excellent point. Perhaps the Paragon representative was just using a figure of speech.

It would be highly unlikely that Paragon has a blast furnace capable of melting iron (2800+ degrees). Highly unlikely....

Ridge-----


I understand that Paragon uses a contract foundry somewhere in the midwest to cast these up. However, it's possible they do the machining in-house.

One benefit of the Paragon manifolds: all original small block manifolds were cast from gray cast iron. I believe the Paragon reproductions are cast from nodular or ductile cast iron which is a better material.

[Ridge K.]

Re: Paragon Repoduction Exhaust Manifold

Ridge-----


I understand that Paragon uses a contract foundry somewhere in the midwest to cast these up. However, it's possible they do the machining in-house.

One benefit of the Paragon manifolds: all original small block manifolds were cast from gray cast iron. I believe the Paragon reproductions are cast from nodular or ductile cast iron which is a better material.

Now that does make sense, Joe.
Thanks.

[Jack H.]

Re: Paragon Repoduction Exhaust Manifold

Methinks you'll be trading the devil you know for the devil you don't know by swapping your existing exhaust manifolds for reproduction... In the end game, what's a 3-point deduction on a 4500 point car???

Is that worth $300 (part + freight & labor to R&R) to you? I think I'd just take the 3-point deduction and know that what's there is actually period real despite prior owner 'touch up'...

[Ronald L.]

Re: Paragon Repoduction Exhaust Manifold

Having been in both foundry and machining, they can't be doing either inside their buildings, we already concluded not on the foundry, machinging will be a similar story. It takes a pretty dedicated set up, unless you are doing these one at a time with a CNC driven by a cad program.

Need to get someone to lay these out side by side.

[Philip A.]

Re: Paragon Repoduction Exhaust Manifold

Another option:
Buy original ($$$); sell your original ($$) and net spend $

[Joe R.]

Re: Paragon Repoduction Exhaust Manifold

Hi Clark:

I bought a '563 from Paragon last year, and compared it to an original. It is very, very close, but the small "nubs" at the casting seam are different in number and size from an original. I'm away from home at the moment, but I can post a photo on Monday if you are interested.

BTW, from my discussions with Paragon I gathered that they have these cast outside, but then Paragon does all the finish machining in-house.

[Jeff B.]

Re: Paragon Repoduction Exhaust Manifold

Any way you look at it, that's an expensive 3 points. I had my exhaust manifolds Metal Sprayed with stainless steel and they look very close to the color and texture of originals - and they will never rust or pit again. I think I also lost 3 points at a regional but I like them! And I still got a 97.8%.

I have attached a picture of the manifold after the Metal Spray process.

[William C.]

Re: Paragon Repoduction Exhaust Manifold

If the manifolds were painted engine orange like the originals (with the engine) you might not have lost the 3 points.

[Joe R.]

Re: Paragon Repoduction Exhaust Manifold

Any way you look at it, that's an expensive 3 points. I had my exhaust manifolds Metal Sprayed with stainless steel and they look very close to the color and texture of originals - and they will never rust or pit again. I think I also lost 3 points at a regional but I like them! And I still got a 97.8%.

I have attached a picture of the manifold after the Metal Spray process.

Jeff,

That's one sharp exhaust manifold, and engine for that matter. Did you send your manifolds to Jerry MacNeish to get the aluminizing treatment? I have not heard of the stainless treatment you mention.

Joe

[Jerry B.]

Re: Paragon Repoduction Exhaust Manifold

What does "cherried up" mean. thanks

[Jeff B.]

Re: Paragon Repoduction Exhaust Manifold

Yeah, you are correct. I just decided that I did not want them painted and then burned off. I did not paint my bell housing either which cost another point of two, but I like it.