I'm sure this has been covered before but did not find a specific answer. I removed my manifolds this weekend because one of the bolts was missing and a couple others were loose and figured the gasket was almost certainly blown out, which it was.

Here's my question. Both sides are stamped "China" so someone has replaced them. That is not automatically bad but the real issue is that one side has a little 2x2" metal plate on the back held in place with a single rivet and what looks to be the remains of a gasket; currently it's rattling around with about a 1/16 gap.

What is that plate for? Should I just replace the manifolds knowing that I'll probably end up with more china stuff anyway? Or, can I braze that plate place in place and call it good? The sealing surfaces look ok and they appear to be straight and level. Would rather spend the money on something more productive.

thx

Jeff

 

Can you post some pictures of this? I guess it could be some sort of heat shield but just not sure what you are talking about.

 

not my picture but this is it.

thx

 

Passenger Cars with FE engines (except 406/427); 1965/67 F100/350 352; 1968/76 F100/350 360/390 did not come with exhaust manifold gaskets from the factory.

Ford installed stainless steel heat shields instead. If exhaust manifold gaskets are present, the manifolds have been R&R'd.

But the pic of that plate in post #3 isn't something that Ford did, as it not a stainless steel shield (that resemble the gypo gaskets).

Right exhaust manifold same: 1965/67 F100/350 352; 1968/76 F100/350 360/390.

Left exhaust manifold same: 1968/72 F100/350 360/390; 1973/76 F100 390; 1973/76 F250/350 360/390; 1975/76 F150 360/390.

Left exhaust manifold machined for a heat riser valve: 1965/67 F100/350 352; 1973/74 F100 360.

 

Thanks, but what is my path forward? Leave that plate rattling around or seal it up? There were gaskets in there and they are available for replacement.

I just got this truck and I'm not looking for performance mods, just leak stoppage.

THX

 

No Ford manifold that I'm aware of has that plate.

I know that, for example, both Fel-Pro and Victor make exhaust manifold gaskets, but Ford never did, because...there were no exhaust manifold gaskets installed originally.

 

This may sound strange, but it's part of your choke pull-off.

Note that what follows may be specific only to 1970.

That plate covers the area that provides a source of heated air to the carb. The two tubes that run from your manifold up to the choke pull-off and carb provide the flow of manifold-heated air. That heated air changes the temperature of the bi-metallic spring in the pull-off and when the spring changes temp, it moves... moving the choke pull-off.

When the engine cools off, the spring cools off, moves back and resets the choke. (Actually, it takes a little more than just that, but that's part of it.)

One of the engine coolant hoses runs past the choke pull-off as well, and I believe it assists in the operation of the pull-off in a similar manner.

Note that the area under that plate is not connected to the passage that the engine exhaust takes.

Back to your specific problem:

The first time I ever had to remove and replace the manifold on the passenger's side, I noticed that the plate was held in place with a large straight-slot screw. After one or two times of having that manifold surfaced, the screw wasn't so identifiable as a screw any more (the slot was gone, ground away during the act of "surfacing" the manifold).

If your manifold has been surfaced previously, it could be that your "rivet" is actually the original screw.

Grind the head away, remove the remainder of the screw (or rivet, if it is actually a rivet), flatten the plate or replace it, re-install with a new high-temperature gasket and new mounting hardware (screw or rivet, as appropriate).

I wouldn't bother looking for that gasket, I'd just cut a new one to fit. Use the plate as a template.

Having the choke pull-off work correctly is a lot more important than it might seem. If your choke doesn't pull off correctly, it could lead to long-term excessive wear in your drivetrain.

 

Take a look at this drawing




That should be enough to get started on the part numbers, if you really want to replace them.

 

WRONG!
Thipdar is exactly right. I've seen numerous manifolds with this setup. It is a factory Ford design.

 

While I appreciate your opinion, I'd caution that we may be talking about two different things.

I agree that it is a design, but I also think that ND is right in that the head-to-manifold interface did not originally use a "gasket". This part of the manifold is a little different, even though it is in the same area; "gasket" and "shield" probably don't apply to the plate, because it doesn't actually mate to the head.

Come to think of it, I doubt that this cover plate needs a gasket either. It covers a cavity that has a tube in it... that tube is part of the air flow circuit for the choke pull-off... and as long as that tube is connected, the choke should work as intended.

What bothers me is that the current replacements for this manifold don't seem to have the tube, or the ability to connect it to the carburetor. this means that the folks that want to run the 1970 choke pull-off may have to search high and low to find the right manifold. OTOH, the tube may be integral to the contemporary replacements, and just not visible in the advertising images. If I ever have to buy a replacement for this manifold, I'm going to proceed with caution.

 

Originally Posted by NumberDummy
No Ford manifold that I'm aware of has that plate.

This is the comment that I say is inaccurate.

Many engines never had exhaust manifold gaskets from the factory, Ford, Chrysler and others. I didn't challenge this statement.

 

I can agree to that.

I wonder if ND confused the plate with a manifold "shield".

 

I quit using gaskets on FE engines decades ago. They tend to be troublesome and blow out. I clean the engine and manifold good, try to get fairly straight with a block sander and some good 50-89 grit and install with high heat silicon like the red or ultra copper. Any leak you have will be barely noticeable.If that plate is loose, knock the rivet out and get rid of it.

 

Well I'll be dipped. I've never run across that plate. Never had a customer ask me to sell them one that is.
The 9A705 did indeed start in 1970 in the Bumpsides. My Ford microfische shows 70/72 F100/350....360/390.....B8AZ9A705B. Nothing else in my 64/72 Ford truck slide.

 

Thanks for all the detailed responses. Since my last post I ground the head off that "rivet" and discovered an opening behind it and no connection to anything. The truck as I bought it has some goofy chrome air cleaner and I'm not sure if it's the original carb because there is nothing hooked up to the choke. Being in San Diego cold weather stuff is seldom an issue.

I ordered a set of gaskets and also ordered a set of the metal heat shields. When those all come I'll put it back together somehow that looks logical. Both manifolds are stamped "china" so definitely not original but seem to be flat. The left side one has a little chunk missing at the donut which is probably a casting flaw. Guess I can braze that in. Hate to spend money on parts when I don't need to.. I took them off in the first place because a couple of the bolts were missing and I assumed they would be leaking, which I found to be true after getting them off. While I'm waiting I chased all the manifold bolt threads with a tap and am standing by for parts.

Before I can drive it I need to put the transmission back in. My friend and I rebuilt the C6 last week.since it was slipping while cold.

Going to post in the van section pretty soon about my 1990 E350 steering box. Never owned a ford in my life and now I have two oldies.

thx again