1967 273 Intake Question

[cuda dad]

I looked up and found this to be the California Emissions manifold. There are two large holes in the manifold. One has a fitting and is capped and the other one is just a threaded hole. The engine runs but it does not have any low end power. The car is manual disc brake, 4-speed. Is there supposed to be a plug or something else in that hole? Thanks!

 

[mopar_nocar]

That LOOKS like a vacuum port...like for power brakes on later stuff. I would grab a 3/8" pipe plug from the hardware store, some teflon tape and plug that thing.

sb

 

[67Dart273]

PLUG!! You should be able to put your finger over that running and see, hear, and feel a tremendous change!!

 

[cuda dad]

PLUG!! You should be able to put your finger over that running and see, hear, and feel a tremendous change!!

It doesn’t seem to make much difference. There seems to be a small amount of vacuum. It could be filled with debris, rat turds and twigs.

 

[65Val]

The small capped one is for power brakes, usually, using a larger fitting. That small fitting looks like it was used for a vacuum gauge or similar.

 

[grjammer]

The small one is for the vacuum "performance" gauge. The large one looks like a temp or vacuum switch boss for optional A/C or power brakes

 

[krazykuda]

The california emissions included a green "vacuum pod" that had three ports... One went to ported vacuum, the other went to manifold vacuum, and the last one went to the vacuum advance pod on the distributor...
\
One of those holes could have had a nipple in it for the vacuum pod....

 

[Cuda Al]

Not sure what that manifold is but this IS a 67 California manifold.

Alan

 

[toolmanmike]

I looked up and found this to be the California Emissions manifold. There are two large holes in the manifold. One has a fitting and is capped and the other one is just a threaded hole. The engine runs but it does not have any low end power. The car is manual disc brake, 4-speed. Is there supposed to be a plug or something else in that hole? Thanks!

View attachment 1715189234

View attachment 1715189235

Looks like vacuum ports. Plug them if you don't need them.

 

[Cuda Al]

I'll have to check the two 4-bbl intakes I have for numbers this afternoon, both 273, neither have that second port.


Alan

 

[66fs]

The OP has a California model. The port goes nowhere. Not sure why it is there.

 

[Dana67Dart]

I bought a 2536771 and it does not have the large port.

There do not seem to be any ports from the cast iron boss to the intake runners or anywhere else.


This is the smaller port that I assume on the 4bbl is for the CAP manifold vacuum like on the 2bbl
4bbl on left 2bbl on right

 

[pishta]

large looks like a power brake booster tap, the blank boss is EGR and the pitiful attempt to route a small port on the intake floor for EGR. If that PB port is open, there is no way the car will run.

 

[Dana67Dart]

Sorry all. My post #12 got a bit confusing. The 4bbl manifold (771) is not installed. the 2bbl (559) is installed and has carb and all hoses run.

I looked up and found this to be the California Emissions manifold

Any idea what year it is IE casting date etc?

My 4bbl (771) is a 66 casting. and my 2bbl (559) should be late 66 to early 67 as I have no reason to believe that it is not the OE manifold

 

[toolmanmike]

Sorry all. My post #12 got a bit confusing. The 4bbl manifold (771) is not installed. the 2bbl (559) is installed and has carb and all hoses run.



Any idea what year it is IE casting date etc?

My 4bbl (771) is a 66 casting. and my 2bbl (559) should be late 66 to early 67 as I have no reason to believe that it is not the OE manifold

The 771 manifold is a 1966 and 67 manifold with CAP.

 

[Dana67Dart]

The engine runs but it does not have any low end power

I found a plastic plug in the vacuum line right in front of the dist vacuum advance which caused the engine to stumble on acceleration. Just a thought.

 

[Dana67Dart]

any thoughts as to why two 771 manifolds would have different ports drilled but have the same part number?

 

[toolmanmike]

any thoughts as to why two 771 manifolds would have different ports drilled but have the same part number?

Same casting number but different part number (application) would be my guess.

 

[pishta]

I think drilled is the key word here. Same casting, same part, one more step for the drilled one. some cranks are like that too. same casting number, way different application.

 

[Dana67Dart]

I think drilled is the key word here. Same casting, same part, one more step for the drilled one

I pulled the intake down from the shelf and examined it thoroughly and there is no where for a hole drilled into the boss to get to manifold vacuum. at best it could get to the valley tray and act as a PCV inlet or outlet. There is very odd casting marks around it on the under side so I can see how a different insert could be substituted and provide passages.
I would love to see the underside of the OPs intake to see how they differ from mine

 

[pishta]

... there is no where for a hole drilled into the boss to get to manifold vacuum. at best it could get to the valley tray and act as a PCV inlet or outlet....

Yeah I see what your describing. No idea. How about PCV? For that clean valve cover look...nah.

 

[pishta]

Here is my 67 273 2bbl intake. I looked up the numbers and they are NHRA recognized for 67. No big *** hole behind the 7/8 runners.
"....
NHRA Tech Department makes additions to the engine blue print specifications
March 6, 2017


The NHRA Technical Department recently added intake manifold casting to the blueprint specifications.

1966 Mopar 273 2536560

1967 Mopar 273 2536559..."

 

[pishta]

Im going to go old school hot-rod and cut out the top of this and epoxy a 4bbl carb spacer in there to make me a ghetto 4bbl. Fill it, sand it, paint it, run it!

 

[Dana67Dart]

I know this is a real old post but...

@cuda dad photo in post #1 is a 2536771 4BBL intake

@Cuda Al post #8 and @pishta post 22 photos show 2BBL intakes

My post #12 shows both my OE 2BBL intake 2536559 mounted on the engine and the loose 2536771 4BBL

My 2536771 4BBL intake has the boss the OP was asking about but it is not drilled, nor does it have any where to go to.

According to NRA site I saw, the 2536771 4BBL is a CAP manifold for 67 model year.

 

[cuda dad]

I know this is a real old post but...

@cuda dad photo in post #1 is a 2536771 4BBL intake

That is correct. Mine is a 1967 California. It is drilled and tapped but is not ported, weird. Doesn't even need to be plugged.