Wildly different manifold flange thicknesses?

[jimmyz80]

On my '31 coupe, the intake manifold recently cracked pretty badly near the carburetor. I have no idea whether either of the manifolds on the car are original. I went online to shop for a replacement and bought what looked like a good one off of eBay. Claimed to be original, had the vacuum port for my wiper, etc.

I went out to install it this evening and the flange that you tighten the nuts down onto, is WAY thicker than the flange on my exhaust manifold. I didn't measure the difference but it looks to be around 1/8". The gasket mounting surfaces appear to be pretty much aligned, and the two manifolds bolt together just fine. It's just the flange thickness that appears to be off. I can't imagine the concave washer would even make contact with the thinner exhaust manifold flange, since it's such a big difference in thickness.

The new intake manifold looks a bit different from the cracked one I removed, and doesn't appear to have a molded-in bung for the vacuum port. Rather it looks like a port was just drilled and tapped into a normal manifold.

Where should I go from here? Should I pick up another intake or exhaust manifold in hopes of finding a matching set? Just bite the bullet and buy a matching reproduction set from one of the vendors? Also curious if there's any way to tell which of my manifolds are original vs. reproduction.

Thanks a ton for any wisdom you may be able to share.

 

[nkaminar]

The one you bought off ebay does not appear to be original. For one thing the tap for the vacuum port does not have the boss. If you have a local club you could let them know that you were looking for an intake manifold. One of the members may have one. Take the exhaust manifold with you to check to see if there is a match. Or buy another one from ebay or craigslist but try to inspect it first. The Barn has a "Swap Meet" forum where people buy and sell stuff. You could advertise there that you were looking for an intake manifold.

I ran an exhaust header on my car for about a month and the exhaust and intake were much different heights, like you show in your photos. I made four L shaped brackets to accommodate the difference that replaced the conical shaped washers. You could do that if you wanted to keep what you have. The L shaped brackets were made from angle iron with a hole drilled in one leg and one leg cut to the difference in height.

 

[dpson]

In the 1970's Model A manifolds were being cast in South America, Argentina I think. The quality of these was fair at best. That might be what you have. Don't mess around with it, get an original or newer reproduction.

 

[J Franklin]

Most will need surfacing to match the exhaust manifold. Bolt them together and run them together to your friendly machinist.

 

[BrianH]

I had mine surfaced at a machine shop. Both sides manifold to engine and manifold to nuts and washers.

 

[jerrytocci]

Make sure gland ring area is deep enough

 

[jimmyz80]

Thanks everyone! I think I may just bite the bullet and use this as an opportunity to buy a new pair of manifolds from Snyders. Not ideal, but beats trying to find a reputable/responsive machine shop around here, or juggling parts to find a matching pair.

 

[john in illinois]

I would get both manifolds from one of our model A vendors.

John

 

[dpson]

I bought a ceramic coated exhaust manifold from Snyders and was very pleased with it. Well worth the money. Also buy the higher end copper manifold gaskets. Again well worth the money.

 

[burner31]

Thanks everyone! I think I may just bite the bullet and use this as an opportunity to buy a new pair of manifolds from Snyders. Not ideal, but beats trying to find a reputable/responsive machine shop around here, or juggling parts to find a matching pair.

You can't find a "reputable/responsive machine shop" in your area?