273 Cracked Intake manifold with a belly of "Charcoal"!

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Mr.Extrodinaire

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I am working on overhauling the original 273ci Motor that came in my 1965 Plymouth Barracuda! I'm pulling parts & working on cleaning them up to restore them to as close to original condition as possible! Already have stripped, cleaned & painted a new oil pan & the 2 original valve covers. I am also in a parallel process of overhauling a 318ci Engine that is a newer 71-73, (haven't narrowed down the mfg date yet) which came out of a "Motorhome" with about 55,000 miles on it. The oil pan is different as well as the timing chain cover is different where the water pump is mounted to a raised position higher up on a specialized timing chain cover location.
So during the process of going thru steps on these things, I pulled off the intake manifold from the 273 & was working to strip off the 59years of gunk from the Intake manifold, which includes removing the rivets from the belly plate to clean the cavity between the plate & the underside of the 2 barrel intake airflow well/ports!
Wow was my expression when I found what appeared to be a stash of coal chunks/flakes & the encrusted coating of hardened crusting along the cast iron cavity! So I went into excavation mode to see what else was hiding inside this historic sarcofigus of ancient records of a failing system. Next I found what an emotional mind never wants to find, but that a rational mind endures to find truth that leads one to where reality can smack your face to wake one up to the truth! A CRACK RUNNING STRAIGHT UNDER THE DEAD CENTER OF THE PASSENGER SIDE INTAKE PORT's "Carburetor Barrel"! Quite possibly the reason why the previous owner gave up on the car & left it to sit in their carport for 20 some years. My guess is that fuell was being fed into the intake, spilling through the crack and being baked into charcoal over time, which also caused overheating of the intake manifold. I just can't figure what would have caused the crack in the first place.
So I seek any info on my current need for a working path forward! I am considering: Cleaning & Brazing the crack in the manifold & rebuilding the carb. I am in Tucson, so water freezing in the intake is not a likely cause of the crack. If anyone has experience or thoughts on the smartest, budget friendly path to matke thing work would be much appreciated!
I do realize life is what happens, regardless as to what our plans are!
Thanks in advance!
 
Mr.Extrodinaire said:
I am working on overhauling the original 273ci Motor that came in my 1965 Plymouth Barracuda! I'm pulling parts & working on cleaning them up to restore them to as close to original condition as possible! Already have stripped, cleaned & painted a new oil pan & the 2 original valve covers. I am also in a parallel process of overhauling a 318ci Engine that is a newer 71-73, (haven't narrowed down the mfg date yet) which came out of a "Motorhome" with about 55,000 miles on it. The oil pan is different as well as the timing chain cover is different where the water pump is mounted to a raised position higher up on a specialized timing chain cover location.
So during the process of going thru steps on these things, I pulled off the intake manifold from the 273 & was working to strip off the 59years of gunk from the Intake manifold, which includes removing the rivets from the belly plate to clean the cavity between the plate & the underside of the 2 barrel intake airflow well/ports!
Wow was my expression when I found what appeared to be a stash of coal chunks/flakes & the encrusted coating of hardened crusting along the cast iron cavity! So I went into excavation mode to see what else was hiding inside this historic sarcofigus of ancient records of a failing system. Next I found what an emotional mind never wants to find, but that a rational mind endures to find truth that leads one to where reality can smack your face to wake one up to the truth! A CRACK RUNNING STRAIGHT UNDER THE DEAD CENTER OF THE PASSENGER SIDE INTAKE PORT's "Carburetor Barrel"! Quite possibly the reason why the previous owner gave up on the car & left it to sit in their carport for 20 some years. My guess is that fuell was being fed into the intake, spilling through the crack and being baked into charcoal over time, which also caused overheating of the intake manifold. I just can't figure what would have caused the crack in the first place.
So I seek any info on my current need for a working path forward! I am considering: Cleaning & Brazing the crack in the manifold & rebuilding the carb. I am in Tucson, so water freezing in the intake is not a likely cause of the crack. If anyone has experience or thoughts on the smartest, budget friendly path to matke thing work would be much appreciated!
I do realize life is what happens, regardless as to what our plans are!
Thanks in advance!
Click to expand...
Well that sucks. 4 barrel right? You can braise it if you have the torch and know how. Or you could find another intake. Place a wanted ad here on the site. Shipping isn't cheap because of the weight. They pop up for sale from time to time. 1965 only for the 4 barrels. Yp, oil splashes onto the hot intake and cokes up. Nasty stuff.
 
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Recycle that cracked intake, or use for a door stop.
 
Replace it unless you have the skill to repair it. It will cost you more to have it fixed than to find a replacement. 65
 
toolmanmike said:
Well that sucks. 4 barrel right? You can braise it if you have the torch and know how. Or you could find another intake. Place a wanted ad here on the site. Shipping isn't cheap because of the weight. They pop up for sale from time to time. 1965 only for the 4 barrels. Yp, oil splashes onto the hot intake and cokes up. Nasty stuff.
Click to expand...
The 273 came with 2 barrel carbs. Later they came with a 4 barrel on a Commando Intake! However, the 4 barrel Commando came after the heads & intake marriage changed the angle for that union. So the 4 barrel Commando Intake I have will go onto the 318 I just got & the 273 will get the repaired original 2 Barrel Intake after I get it brazed!
I am actually an Army Trained Metal Worker, although I do not currently have access to the equipment (oxy-acetaline) tanks & torch here in Tucson.
 
Mr.Extrodinaire said:
The 273 came with 2 barrel carbs. Later they came with a 4 barrel on a Commando Intake! However, the 4 barrel Commando came after the heads & intake marriage changed the angle for that union. So the 4 barrel Commando Intake I have will go onto the 318 I just got & the 273 will get the repaired original 2 Barrel Intake after I get it brazed!
I am actually an Army Trained Metal Worker, although I do not currently have access to the equipment (oxy-acetaline) tanks & torch here in Tucson.
Click to expand...
Well yes but no. The 64's had 2 barrel only. The 65's came with 2 and 4 barrel intakes that had the same 5/16" bolts at the odd angle. In 1966 the bolts changed to 3/8" and the normal bolt angle that all the small blocks had up until the Magnum engines came out in the early 90's. The bolt holes in the heads were what changed in 1966 so the earlier heads and intakes must match or modifications made.
 
Mr.Extrodinaire said:
The 273 came with 2 barrel carbs. Later they came with a 4 barrel on a Commando Intake! However, the 4 barrel Commando came after the heads & intake marriage changed the angle for that union. So the 4 barrel Commando Intake I have will go onto the 318 I just got & the 273 will get the repaired original 2 Barrel Intake after I get it brazed!
I am actually an Army Trained Metal Worker, although I do not currently have access to the equipment (oxy-acetaline) tanks & torch here in Tucson.
Click to expand...
The 4BBl Commando Intake came in '65...
Here's what it looks like.

1.jpg
 
I can tell you from experience that if you try to mount the "new angle" 4bbl intake on a set of early heads, you will get burned oil gunk on the valves and all kinds of crap in the valley — it will leak on both sides.
 
Do you have mfg. part numbers for the intake & carb? I believe to original intake & engines were painted red directly out of the Chrysler Factories!
I believe that some of what I'm seeing in recent posts are aftermarket or Dodge parts.
Mine is a 1965 Plymouth Barracuda & I am unaware of the dispersement of the 273's!
For my Barracuda, it shows that the 1964 production year produced: A Straight 6, A Slant 6 & A 273V8 were the only options for the 1965 Model Year! I am not aware of a 4 Barrel Factory Model Year Option Available for my car.
 
Mr.Extrodinaire said:
Do you have mfg. part numbers for the intake & carb? I believe to original intake & engines were painted red directly out of the Chrysler Factories!
I believe that some of what I'm seeing in recent posts are aftermarket or Dodge parts.
Mine is a 1965 Plymouth Barracuda & I am unaware of the dispersement of the 273's!
For my Barracuda, it shows that the 1964 production year produced: A Straight 6, A Slant 6 & A 273V8 were the only options for the 1965 Model Year! I am not aware of a 4 Barrel Factory Model Year Option Available for my car.
Click to expand...
Of course the 4 barrel 273 came out in 65 as I stated in post #8 above. The intake is # 2465726. The carbs were Carter AFB's and the numbers were 3853S for manual transmission and 3854S for automatic.

engine 296c.jpg
 
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Mr.Extrodinaire said:
Mine is a 1965 Plymouth Barracuda & I am unaware of the dispersement of the 273's!
For my Barracuda, it shows that the 1964 production year produced: A Straight 6, A Slant 6 & A 273V8 were the only options for the 1965 Model Year! I am not aware of a 4 Barrel Factory Model Year Option Available for my car.
Click to expand...
That's because your not listening...

and There was not a Straight 6, You didn't find That info here.
 
Mr.Extrodinaire said:
Do you have mfg. part numbers for the intake & carb? I believe to original intake & engines were painted red directly out of the Chrysler Factories!
I believe that some of what I'm seeing in recent posts are aftermarket or Dodge parts.
Mine is a 1965 Plymouth Barracuda & I am unaware of the dispersement of the 273's!
For my Barracuda, it shows that the 1964 production year produced: A Straight 6, A Slant 6 & A 273V8 were the only options for the 1965 Model Year! I am not aware of a 4 Barrel Factory Model Year Option Available for my car.
Click to expand...
yes the 4bbl was available in late 1964 and 1965. Follow what Toolman Mike is telling you and you will be golden. My car was built in late 64 and has the 273 commando 4 bbl. The bolt angle was changed for the 1966 model year so if you have an early one for sure use the part number Mike posted. If you are not dead set on original the Edelbrock D4B is a good choice but again it is for the early 273.
 
you can weld the rack with cast welding rod, muggy rod is the best one to use, its made in wash state. they have a web site. far better than brazing.
 
Seeing as how you're building an early 70's 318-3 motor, I'd ditch those water crossover heads with the 18mm plugs, get some later heads with hardened seats, and a later intake to match whatever horsepower and carb you desire. The later parts are much easier to find and a lot less coin.
 
Mr.Extrodinaire said:
The 273 came with 2 barrel carbs. Later they came with a 4 barrel on a Commando Intake! However, the 4 barrel Commando came after the heads & intake marriage changed the angle for that union. So the 4 barrel Commando Intake I have will go onto the 318 I just got & the 273 will get the repaired original 2 Barrel Intake after I get it brazed!
I am actually an Army Trained Metal Worker, although I do not currently have access to the equipment (oxy-acetaline) tanks & torch here in Tucson.
Click to expand...
"However, the 4 barrel Commando came after the heads & intake marriage changed the angle for that union." Nope. The 4bbl Commando/Charger started in 1965 with 5/16 intake bolts at the 'wrong' angle. For 1966 they switched the intake bolt angle and swapped out for 3/8-16 bolts.
 
Later model 318 heads on a 273, with an Edelbrock D4B made for a 64-65 273 sitting on it to show the bolt angle difference. 64-65 model 273 heads would show the bolt gap opposite of what it is.

IMG_1741.JPG
 
Mr.Extrodinaire said:
I believe that some of what I'm seeing in recent posts are aftermarket or Dodge parts.
Click to expand...
273's for the Dodge and Plymouth are the same except for the 4bbls where they got different stickers on the chrome air cleaner; Charger 273 for Dodge and Commando 273 for Plymouth. Some of what you are seeing are aftermarket aluminum intakes (primarily Edelbrock) but "Dodge Parts" are not aftermarket.... Hell, my 66 Barracuda 273 4bbl came with a Charger 273 Air Cleaner...at delivery. Not unusual as it was made on the same line with Darts at Hamtramck/Dodge Main
 
cudamark said:
Except you have the wrong valve covers and thermostat cover for a '65-6, and misc other hose and hardware changes.
Click to expand...
Wrong? I never said it was a Commando! :p

M1.jpg

and considering what it was I think it looks pretty damn good! (and I didn't like the Angled Nose on the Thermostat Cover)
 
Mr.Extrodinaire said:
I am working on overhauling the original 273ci Motor that came in my 1965 Plymouth Barracuda! I'm pulling parts & working on cleaning them up to restore them to as close to original condition as possible! Already have stripped, cleaned & painted a new oil pan & the 2 original valve covers. I am also in a parallel process of overhauling a 318ci Engine that is a newer 71-73, (haven't narrowed down the mfg date yet) which came out of a "Motorhome" with about 55,000 miles on it. The oil pan is different as well as the timing chain cover is different where the water pump is mounted to a raised position higher up on a specialized timing chain cover location.
So during the process of going thru steps on these things, I pulled off the intake manifold from the 273 & was working to strip off the 59years of gunk from the Intake manifold, which includes removing the rivets from the belly plate to clean the cavity between the plate & the underside of the 2 barrel intake airflow well/ports!
Wow was my expression when I found what appeared to be a stash of coal chunks/flakes & the encrusted coating of hardened crusting along the cast iron cavity! So I went into excavation mode to see what else was hiding inside this historic sarcofigus of ancient records of a failing system. Next I found what an emotional mind never wants to find, but that a rational mind endures to find truth that leads one to where reality can smack your face to wake one up to the truth! A CRACK RUNNING STRAIGHT UNDER THE DEAD CENTER OF THE PASSENGER SIDE INTAKE PORT's "Carburetor Barrel"! Quite possibly the reason why the previous owner gave up on the car & left it to sit in their carport for 20 some years. My guess is that fuell was being fed into the intake, spilling through the crack and being baked into charcoal over time, which also caused overheating of the intake manifold. I just can't figure what would have caused the crack in the first place.
So I seek any info on my current need for a working path forward! I am considering: Cleaning & Brazing the crack in the manifold & rebuilding the carb. I am in Tucson, so water freezing in the intake is not a likely cause of the crack. If anyone has experience or thoughts on the smartest, budget friendly path to matke thing work would be much appreciated!
I do realize life is what happens, regardless as to what our plans are!
Thanks in advance!
Click to expand...
Or put a set of 66 and later heads on it. Opens a whole new world.
 
My 273 has a 2 Barrel Intake & the original B&B 2 Barrel! Not sure why oil would be "Splashing onto the intake on the underside of of the Carb Injection Ports which should only allow for heated exhaust is ported beneath the intake, as I said, below or under the intake ports.
There are 2 center exhaust ports from the exhaust manifold which allows the heated exhaust to go into the Under Belly cavity to heat the fuel & warm the air as both enter through the Carburetor & dispersed to the cylinders. So I guess that if there is excessive blowby due to bad piston rings, oil could be being blown into this "BELOW THE BOTTOM OF THE FUELED INTAKE PORTS! The "Underbelly Chamber" is not an airtight feature as a thin steel plate is simply riveted on & exhaust gases would easily escape the 360° perimeter of the intake manifold's belly plate. I called this massive buildup, CHARCOAL, Because it is exactly what it looks like a the fact that the entire cavity was filled with Baked "Fuel&Oil" that formed large hardened chunks & layered flakes residual debris. Rationally, fuel which could have leaked thru the cracked cast iron intake, as I stated, centered under the passenger side carb barrel . The intake crack runs from the front to the rear of the underside of the chamber to the front, is about 4" long & is more than just a hairline crack. I didn't see it until the packed full, coal storage was removed & a I used a small wire brush to remove the hard baked layers. Since This is not a hard pressed, urgent project, I may just sandblast the intake & use Extreme Heat, JB Weld until I get it running. Money is tight, & it won't be running overnight!
Once I know, it to be a viable project, I can shoot at the stars, for a 4 Barrel Miracle, 273! I am guessing, this is a rare machine.
I mean it is one of the earliest Barracudas!


toolmanmike said:
Well that sucks. 4 barrel right? You can braise it if you have the torch and know how. Or you could find another intake. Place a wanted ad here on the site. Shipping isn't cheap because of the weight. They pop up for sale from time to time. 1965 only for the 4 barrels. Yp, oil splashes onto the hot intake and cokes up. Nasty stuff.
Click to expand...
 
Mr.Extrodinaire said:
My 273 has a 2 Barrel Intake & the original B&B 2 Barrel! Not sure why oil would be "Splashing onto the intake on the underside of of the Carb Injection Ports which should only allow for heated exhaust is ported beneath the intake, as I said, below or under the intake ports.
There are 2 center exhaust ports from the exhaust manifold which allows the heated exhaust to go into the Under Belly cavity to heat the fuel & warm the air as both enter through the Carburetor & dispersed to the cylinders. So I guess that if there is excessive blowby due to bad piston rings, oil could be being blown into this "BELOW THE BOTTOM OF THE FUELED INTAKE PORTS! The "Underbelly Chamber" is not an airtight feature as a thin steel plate is simply riveted on & exhaust gases would easily escape the 360° perimeter of the intake manifold's belly plate. I called this massive buildup, CHARCOAL, Because it is exactly what it looks like a the fact that the entire cavity was filled with Baked "Fuel&Oil" that formed large hardened chunks & layered flakes residual debris. Rationally, fuel which could have leaked thru the cracked cast iron intake, as I stated, centered under the passenger side carb barrel . The intake crack runs from the front to the rear of the underside of the chamber to the front, is about 4" long & is more than just a hairline crack. I didn't see it until the packed full, coal storage was removed & a I used a small wire brush to remove the hard baked layers. Since This is not a hard pressed, urgent project, I may just sandblast the intake & use Extreme Heat, JB Weld until I get it running. Money is tight, & it won't be running overnight!
Once I know, it to be a viable project, I can shoot at the stars, for a 4 Barrel Miracle, 273! I am guessing, this is a rare machine.
I mean it is one of the earliest Barracudas!
Click to expand...
The passages in the intake work with the heat riser valve in the passenger side exhaust manifold. When cold, the valve is closed and hot exhaust travens under the intake plenum to ease in cold drivability. S the engine warms, so does the thermostatic spring on the heat riser valve and the vale opens sending the exhaust through the manifolds and out the tail pipe. It is coke, charcoal or whatever you choose to call it. Take some Vice Grips and unscrew the rivets from the tin under the intake. Clean there and in all the ports you can get to. You can block off the openings in the intake gasket if you wish. Make sure the heat riser is open all the time if you do so. If your intake is cracked you still need to deal with that. I would find it easier to find an good used one. The 2 barrel intakes are much easier to find than the 4 barrel ones. Just place a want ad here.
 
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