Help with manifold

[landarts]

I purchased a 68 1/2 ton about a week ago and trying to get it running. The truck has sat for a long time with bad gas left in the tank and fuel system. I am working all items to be cleaned out or replaced to get it going. The motor is a 283 and had a rebuild on it about 30K ago. I knew that the carburetor would need to be removed and rebuilt. When I tried to remove the carburetor the two front stud mounts basically were rusted through and snapped of with the slightest pressure. The two back ones were fine and no signs of rust.

I proceeded to pull of the intake manifold so I could work on getting the rusted carburetor mounts out and the threads cleaned up. As I was working on it I remembered that I had two intake manifolds from 327 motors. When I flipped them over to compare I noticed that the 327 manifold had the middle most port blocked off and the manifold from the 283 had the middle port open.

Is it ok to use the 327 manifold with ports closed or do I need to stick with the 283 manifold and get the carburetor studs fixed.

Pict 1 is the broken off studs in the 283 manifold
Pict 2 is the two side by side for comparison
Pict 3 is the truck I bought

[71meangreenc10]

Nice truck...

Basically you would be doing what is in this article:
https://www.jalopyjournal.com/forum/...risers.247422/

If it is fine with you, do it. Are you using a Divorced Choke/Cable Operated/Electric Choke? A blocked port would affect the Divorced one in the cold.

Smitty

[landarts]

Originally Posted by 71meangreenc10

Nice truck...

Basically you would be doing what is in this article:
https://www.jalopyjournal.com/forum/...risers.247422/

If it is fine with you, do it. Are you using a Divorced Choke/Cable Operated/Electric Choke? A blocked port would affect the Divorced one in the cold.

Smitty

Right now on the truck is a cable operated choke. The carburetor is a two barrel Rochester 2 Jet.

[71meangreenc10]

That may not matter in your situation. Use either or....

Smitty

[weq92f]

.
...and now that you know...you can also get a set of gaskets that block those ports effectively disabling the heat risers. It's what I did on my BBC to help keep the intake cooler and minimize heat soak issues ( was having warm starting problems ).

Hth,

-klb

[randy500]

The blocked passage is from carbon build up. Just drill and chisel it out.

[AussieinNC]

Set the original manifold up in a drill press and drill out the original broken studs. If you need to, go one size bigger and use a helicoil to bring the thread back to standard size.

If you use the replacement manifold, clear out the carbon choked ports....

[BigBird05]

The 327 manifold is showing some rust in the #1 and #2 intake runners. That one will requier some clean up work. In the area of staying "original" I would fix the 283 manifold. Try soaking the studs with PB Blaster for a few days then try an EZ out.

[68 P.O.S.]

Originally Posted by randy500

The blocked passage is from carbon build up. Just drill and chisel it out.

I agree

[weim55]

Your 327 intake has considerably larger intake port opening so there will be a significant port size mismatch with the cylinder heads if they are correct for a 283. On a stock engine the port mismatch is unnoticeable in performance but if you use the 327 intake check very carefully that the larger ports don't create a vacuum leak at the port. If it were me I'd repair and run the 283 intake but I also have a torch setup that will almost certainly be required to get those broken studs out.

OR, hit the parts board here and post a WTB for a correct '68 307 intake setup and put her back to all original...........

Steve weim55 Colorado

[landarts]

I am leaning toward trying to fix the old 283 manifold. Ordered a Helicoil kit and have them soaking right now with Kroll oil. I will report the progress here shortly.

[landarts]

Well I soaked the two carburetor mounts that were broken off with Kroll oil a couple times a day for three days. Then I center punched it a few times with a carbide center punch and started drilling with a small bit and worked my way up in size. Going slow and adding some cutting lubricate as I go. I added a little heat with a Map gas torch and kept drilling and the first one finally came out on the drill bit. Moved onto the second one and had to go all the way, then used a 5/16 18NC tap and retapped it. Then used the tap to chase down the other three mount holes. When it was good and tested the mount screws, then took it out to side of garage and sprayed it down with dollar store oven cleaner to get all the gunk off and get it ready to reinstall.

[AussieinNC]

I dont see a problem with your collection....



if you run out of space you could always send me a few to look after for ya...