273????

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custom100 said:
Hi guys/gals

Well I'm finaly getting to the point where I can start on my 65 Valiant, the apprenticship is done and the bills are almost all payed off.

So I now have a couple of questions.

I was thinking of doing some work to my 273 to make it more like the comando motor. Though I have heard that to put a 4brl in take on the 65 LA motor it's a one year only is this true?

Then what was the difference inthe heads on a comando and the regular 273?

Now to through a hole wrench into things I have a set of 340 J heads as well. I was thinking of using these, is there any advantage to these heads or would they be to much for a 273?

And last I do have a line on a 340 should I just bag the 273 and go to the 340?


Thank you guys/gals for all your Imput

Austin
Click to expand...
The commando was a beefer cam, high compression, intake and carb.
Do not use the J heads on that motor. They are way to big.
 
clifftt said:
I'm just about finished with my '64 273, hopefully going back in the car in the next week or two. Man, what a pain it has been to get parts....030" over pistons, had to weld up nasty corrosion pits in the timing cover since the new covers have you re-route the lower rad hose, limited options for intake manifold and solid cam, conversion to hydraulic cam & lifters.... In the end, I'll have about $2300 into parts, machining, balancing this motor (includes a valve job). I'll have the satisfaction of doing it myself, but I could have got a more powerful 318 professionally built for less. If I had to do it over again, I'd go the 318 route. My two cents.....
Click to expand...

I had to replace my timing cover too, but they are easy to find. Look for poly 318 timing covers. Its the exact same part. I sleeved the cylinders in my block instead of over sized pistons, used 85' 318 swirlport heads and now can use any intake I want. The only thing you have to do to convert from a solid lifter cam to a hyd. is swap the cam and lifters and buy longer pushrods. You can reuse the adjustable rockers.
 
Depends on what you want to do with the car.

1. Roast the tires down the street.
2. Daily driver.

I have a '67 Commando Barracuda which I drive daily. I love it and wouldn't have it any other way. It gets about 20 mpg and has plenty of passing poop. Plus, it's nice and quiet for driving around town so I can also listen to music or talk to the person in the car with me.

I also have a '64 Barracuda with a 340. It's mildly built, so it's fun to thrash on. I like to not have to drive it all the time though for economical reasons, and consideration of my nervous system. I guess that makes me old. I don't want to always be driving a car that chomping at the bit.
 
Wow thinks guys this is a lot of information and it has helped me to deside to do the 273 and pass on the 340 (for now).

Now I have another question if I'm reading correctly the valve size was the same for the regular 273 and the 273 comando? Would there be any improvement in going to larger valves and is there room?

Austin
 
Bigger valves will just interduce shrouding problems. You are better off porting the 273 heads and keeping the same size valves.
 
No room for oversize valves with stock bore 273.
No room for 360/heads either because the valves are too big.





custom100 said:
Wow thinks guys this is a lot of information and it has helped me to deside to do the 273 and pass on the 340 (for now).

Now I have another question if I'm reading correctly the valve size was the same for the regular 273 and the 273 comando? Would there be any improvement in going to larger valves and is there room?

Austin
Click to expand...
 
Hell_Fish said:
I sleeved the cylinders in my block instead of over sized pistons, used 85' 318 swirlport heads and now can use any intake I want. The only thing you have to do to convert from a solid lifter cam to a hyd. is swap the cam and lifters and buy longer pushrods. You can reuse the adjustable rockers.
Click to expand...

I was going to use the 1985 318 swirl port heads on my 273 too, they are easy to find in the junk yard and have the same valve size as the 273. The casting number ends in 302. Its a closed chamber head and then you can use flat top pistons to get a good quench, its also very efficient (compared to 273 heads) and you can use any modern 318 manifold. I was planning on using an older LD4 manifold from Edelbrock I see them on Ebay every so often.
 
You want an Ld4B intake for a 273/ 318.

Cast # 302 heads work great stock on a 273/318 too,
if you want to go to newer heads.

Rob64GT said:
I was going to use the 1985 318 swirl port heads on my 273 too, they are easy to find in the junk yard and have the same valve size as the 273. The casting number ends in 302. Its a closed chamber head and then you can use flat top pistons to get a good quench, its also very efficient (compared to 273 heads) and you can use any modern 318 manifold. I was planning on using an older LD4 manifold from Edelbrock I see them on Ebay every so often.
Click to expand...
 
So if I use the 318, 302 heads can I use any intake or am I still limited to the early still ones?

I also take it that the 302 heads flow better, and would it be worth looking for these heads?
 
custom100 said:
Wow thinks guys this is a lot of information and it has helped me to deside to do the 273 and pass on the 340 (for now).

Now I have another question if I'm reading correctly the valve size was the same for the regular 273 and the 273 comando? Would there be any improvement in going to larger valves and is there room?

Austin
Click to expand...

You can take a 1.88 and cut it down to 1.84 without worrying about shrouding, same on the exhaust valve. With a little bowl blending you can get that 273 flowing just as good as the 302, maybe better. My heads flowed at 167 cfm @ .500 of lift, 116% max velocity. More than enough for a street 273.

Remember that you can bump up your cr with 8.8 cr by milling the heads and using a thinner gasket. Good enough for a street motor.
 
custom100 said:
So if I use the 318, 302 heads can I use any intake or am I still limited to the early still ones?

I also take it that the 302 heads flow better, and would it be worth looking for these heads?
Click to expand...

Cast # 302 heads you can use any 1966 and newer intake.

The old Edelbrock LD4B is made for the 318 and 273,
it has smaller ports to keep the velocity higher,
and in my old fart opinion is about the best intake,
for a 273/318, unless you can find an old heavy cast iron 4bbl 273 one.

The #302 heads are decent out of the box.

I am using the # 302 heads, I didn't have them ported,
only milled enought to clean them up.

Now the big question,
are you going to race the car, do you have 3.90 gears,
or 4.11 etc??

If your going to mostly street drive the car,
don't go crazy trying to get an extra 20 hp,
keep it simple.
Dual exhaust off the stock manifolds is a great place to start.

Here is my 318 with the Ld4B intake,
the 273 timing cover, water pump, exhaust manifolds etc.
 
Ok so it sounds as though I may be better off with the 302's so I'll have a look around. I have a 72 318 in the car right now so I may have a look there.

I know why don't I just do up the 318, I was thinking it would be cool to do up the # machining motor. Though I may do up the 318 if the 273 does not work out.

Austin
 
The standard Edelbrock Performer , not the RPM, has the smaller ports too...and is the only aftermarket intake I've seen with the offset water neck, important if you have plans to use the late model Jap built aluminum AC compressor. Or want to put a 4 barrel on a late model 318 in a Ram truck or something.
alan627b
 
custom100 said:
Ok so it sounds as though I may be better off with the 302's so I'll have a look around. I have a 72 318 in the car right now so I may have a look there.

I know why don't I just do up the 318, I was thinking it would be cool to do up the # machining motor. Though I may do up the 318 if the 273 does not work out.

Austin
Click to expand...

There is no VIN number on a 273.

Starting in late 1968, Chrysler began stamping the last eight digits of the car's serial number on the rear of the engine where the block and transmission meet. In 1969, the VIN stamping was moved to the lower passenger side of the block. Early 1969 models used the full VIN while later models used only the last eight digits. Warranty engines will have no numbers on this pad. If the number differs from the car's VIN tag, the engine was probably taken from another car and would not be considered "numbers-matching."
 
if i were you i would build the 340... its going to be cheeper and more parts avilable.. . you will be able to run a better (more dir and lift) cam ..better manifold.i think you said you also have a pair of j heads ,if so you could realy make some hp..use the 273 rockers .i use them on my race 360 moter no problems . the 904 will be ok..the only problems are no aftermarket shifter for the two cables...and the torque conveter will be trouble,because they used a smaller size input shaft..up to 66 ...Rick at A@Atrans can help you with that ...i run a 64 904 trans in my 64 360 dart race car.. using 64 65 consol floor shifter.a late model in put /reacter asysm a with 5 clutch front drum and 5clutch rear drum all from A@A NO PROBLEMS a 4200 stall convertor from dynamic...12.3 ALL DAY A1.69 60FT A@A number 317 831 3066 dynamic number 877 846 5876 good luck
 
It's interesting to read the for-and-against posts about the 273. I personally like the HP273. My first car had a HP273 and my present car has the same.
I know it would probably be easier and cheaper to just put in a 318-340-360-408 stroker-new style hemi-etc-etc-etc. There some of us that choose and respect what the 273 is. It's the underdog. "No torque on the bottom end"
is what I hear. As long as I can let the clutch out in first gear and spin the tires who cares. Most of us don't want to build an all out race motor capable of *** horse power at *** rpm. We just want a 273 that is fun to drive, can spin the tires when we want, and because of the design, can get 20 mpg.
(that's just a bonus). Keep the positive 273 posts going. I own one and I'm a believer. (ps to all you other guys, I respect what you do with your cars. I would love to have a pro street 64 Dart with a 408 stroker. My 66 Dart is
pretty close original so that's why I like my HP273.. toolmanmike
 
toolmanmike said:
It's interesting to read the for-and-against posts about the 273. I personally like the HP273. My first car had a HP273 and my present car has the same.
I know it would probably be easier and cheaper to just put in a 318-340-360-408 stroker-new style hemi-etc-etc-etc. There some of us that choose and respect what the 273 is. It's the underdog. "No torque on the bottom end"
is what I hear. As long as I can let the clutch out in first gear and spin the tires who cares. Most of us don't want to build an all out race motor capable of *** horse power at *** rpm. We just want a 273 that is fun to drive, can spin the tires when we want, and because of the design, can get 20 mpg.
(that's just a bonus). Keep the positive 273 posts going. I own one and I'm a believer. (ps to all you other guys, I respect what you do with your cars. I would love to have a pro street 64 Dart with a 408 stroker. My 66 Dart is
pretty close original so that's why I like my HP273.. toolmanmike
Click to expand...

Lets see some pics of your HP car
 
It needs work but I have a lot of fun with it............That's what its all about..Mike First photo is when I picked it up. second is somewhere in between and the third is at Mopars on the Mississippi in Dubuque a couple of years ago. Thanks for listening. Mike
 
Hey guys I like the debate thats going on as well, I have to admit I'm still not sure what I want. Though I am leaning towards the 273, only because it's the original motor. Well ok it will also give an reason to build another car with a 340, cause if you have one well two would be better right.

With the small displacement of the 273, how does it handle high RPM? I would think that it would like it.
 
toolmanmike said:
It needs work but I have a lot of fun with it............That's what its all about..Mike First photo is when I picked it up. second is somewhere in between and the third is at Mopars on the Missippi in Dubuque a couple of years ago. Thanks for listening. Mike
Click to expand...

Real nice 4 gear car, really hard to find out my way. I've been looking for one for quite some time but all you can find are major rust repair projects.
 
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