273 special parts

[Dana67Dart]

My understanding is Commando 273s were identical to 2bbl 273s EXCEPT for cam, pistons, rings and valve springs (due to the cam), dist, intake, carb, and the dress up parts - air cleaner, valve covers.

The parts book in 67 confirms this as only one crank is listed, one head, one rod etc.

 

[RustyRatRod]

1964-1967 were all solid lifter cam engines. In 68 they changed to hydraulic and stamped rockers. 1969 was the last year of the 273.

Were there any Commandos with hydraulic cams and stamped rockers? I didn't think there was but.....

 

[Dana67Dart]

Were there any Commandos with hydraulic cams and stamped rockers? I didn't think there was but.....

According to the 68 and 69 FSM

68 Plymouth no listing for a 4 bbl 273 or 318
69 Dodge no listing for a 4 bbl 273 or 318

It looks like 273 Commando died in 67 which makes sense with the introduction of the 340 in 68

 

[Cuda Al]

Internally the only differences are the cam and pistons.
The crank, rods, lifters, rockers are all the same as the 2 bbl.


Alan

 

[Darter6]

67 was a transition year. Pretty crazy to keep track of.

Ill say !

 

[junkyardhero]

67 first year of LA 318 except Canada.

68 was an odd year for 273 as 318 fit in the same places.

Kinda rare to see 68 273 cars, especially B body, but it was available.

my 68 dart has (had) a 273 and the 68 barracuda had a 318

 

[cudamark]

Were there any Commandos with hydraulic cams and stamped rockers? I didn't think there was but.....

Nope

 

[RustyRatRod]

Nope

Thanks. I didn't think so, but my 273 knowledge is limited. Hell, all my knowledge is limited. lol

 

[cudamark]

According to the 68 and 69 FSM

68 Plymouth no listing for a 4 bbl 273 or 318
69 Dodge no listing for a 4 bbl 273 or 318

It looks like 273 Commando died in 67 which makes sense with the introduction of the 340 in 68

Not only just those years, but, even though there were factory A318 4bbl's, there were no factory LA318's with a 4bbl until 1978......not counting marine and industrial stuff.....

 

[cudamark]

My understanding is Commando 273s were identical to 2bbl 273s EXCEPT for cam, pistons, rings and valve springs (due to the cam), dist, intake, carb, and the dress up parts - air cleaner, valve covers.

The parts book in 67 confirms this as only one crank is listed, one head, one rod etc.

At least in 1966, the valve springs and rings are the same between 2bbl and 4bbl.

 

[cudamark]

Thought the LA teen came out in 67? I know I was surprised to see a 67 Belvedere with a 73 in it.....

They did in some models as mentioned. The '67 LA318 also came with a forged crank. Most '68-up (but not all) 318's came with a cast crank. Some trucks and industrial applications also came with forged cranks.

 

[Dana67Dart]

Internally the only differences are the cam and pistons.

the valve springs have a different Lbs at the same lift 4bbl to 2bbl. could be shims or keepers but makes more sense to be different valve springs

 

[Dana67Dart]

At least in 1966, the valve springs and rings are the same between 2bbl and 4bbl.

from 66 Dodge FSM

The FSM indicate different spring pressure at the same lift, BUT it might be from shims????

single asterisk is 2bbl double asterisk is 4 bbl

 

[volaredon]

What heads would they have had?

 

[toolmanmike]

What heads would they have had?

64 and 65 had #315's or #080's. 66's and 67 had #178's, #234's or #920's. 68 and 69's had #679's. The 679's were open chambered.

 

[Bodyperson]

Interesting, some models had both the 273 and the 318 available. Others just had the 318. For instance, according to my Galen book, Barracuda's didn't get the 273 but got the 318. Probably because the 340 was available in that model in 67. I don't see 273's available in any Coronet's or Chargers but they were available in the Belvedere's and Satellites along with the 318's (including the wagon's but the 273 wasn't available in the sport models like the Sport Satellite unless it was a wagon. 67 was a transition year. Pretty crazy to keep track of. The rarest one listed with a 273 is a 68 Sport Satellite 9 passenger wagon. 393 produced. No transmission breakdown though. .

I don't think you could get a 340 in 1967 anything.

 

[toolmanmike]

I don't think you could get a 340 in 1967 anything.

You're right. 68

 

[Jeebis44]

If factory, they are closed chamber heads and have value. They dont flow "much" but we're a good combo for the Commando motor. Yes there is value, condition dependent.

It’s interesting to study the trade offs between higher flowing open chambers VS closed chamber and higher compression, built for proper “quench” distance

 

[Jeebis44]

@Jeebis44 Be sure to look at the pistons to see if they are oversized. You can sell those to someone needing to bore their motor. Someone may want the 920 heads if you sell them cheap enough to make shipping worth it.

As far as availability of 273's in A body cars, we have a numbers matching 69 Dart GT conv that is a 273 car. I've got a set of Race Tech custom flat tops for it, and making plans to use Magnum heads and factory Magnum OBDII fuel injection on it when time comes to fix it. I wanted to make it a one of none 69 Dart Swinger conv....but my wife ain't havin it since it's her car...lol.

Hughes engines makes a set a magnum heads that have LA intake bolt pattern. Ran them on a 318 and it really woke that thing up

 

[toolmanmike]

It’s interesting to study the trade offs between higher flowing open chambers VS closed chamber and higher compression, built for proper “quench” distance

I doubt if the open chamber heads were much better flowing. If so, just by a small amount.

 

[Jeebis44]

67 first year of LA 318 except Canada.

68 was an odd year for 273 as 318 fit in the same places.

Kinda rare to see 68 273 cars, especially B body, but it was available.

Had a ‘66 Fury 3 and came with the poly 318 in it. That was a stump puller engine and ran very well - better with a 3x2 intake. Sold that intake / carbs to a guy in Sweden years ago…

I doubt if the open chamber heads were much better flowing. If so, just by a small amount.

yeah, personally I’d rather have all the benefits of proper quench

 

[JDMopar]

Hughes engines makes a set a magnum heads that have LA intake bolt pattern. Ran them on a 318 and it really woke that thing up

Thanks. I've already got the factory magnum beer keg intake and whole fuel injection system with the harness. It's my wife's car, so MPFI will be the best for her. She has the patience of a Honey Badger, so I can just see her dealing with a carburetor!

 

[Jeebis44]

Thanks. I've already got the factory magnum beer keg intake and whole fuel injection system with the harness. It's my wife's car, so MPFI will be the best for her. She has the patience of a Honey Badger, so I can just see her dealing with a carburetor!

lol - just got back from deployment with the Navy and had left the wife with one car with no choke (Cuda) and one with manual choke (‘66 fury 3), and both with no power steering or brakes. Needless to say they had just sat for over a year…

 

[cudamark]

64 and 65 had #315's or #080's. 66's and 67 had #178's, #234's or #920's. 68 and 69's had #679's. The 679's were open chambered.

The '68-74 318 heads are 675 castings.

 

[Miranthis]

the 4BBL AFB carbs. 4 different # ones each year. M/t, A/T, CAP A/T, and CAP M/T. The exhaust manifolds and the intake (65 and 66 4bbl intakes are different bolt hole geometries).