273 4bbl, carb replacement?

[4spdragtop]

No expert here, and although the 273 has been super reliable we didnt have the performance we thought we would. I wont say what to do or to avoid(no expert). Car is a 67 S, we got original block and intake.(no commando pistons)
We also got another complete 273 that started life as a 2bl.
Heres what we did..
Comp cams and lifters 270-s( too big).
Comp dbl timing chain and gears.
New Eddy 1405(or6) carb.
We left original 323 SG in, and we had 2 torque converters. To be honest both unknown.
That's basically it. 2bl pistons, too big of a cam, unknown tc and 323 gears.
Smaller cam, bigger gears and a new known tc would have made a world of difference. Also commando pistons are very expensive. New landed at my door would be approx $1000.
I'm done sinking $$ in the 273, I dont regret it cuz Dad n I had a blast building it together with a ton of help from fabo.
BUT how much engineering went into the Ddart 273...a lot. And how much hp did they get? I dont think over 300hp?
A different small block is on the stand waiting for me to finish it up.
Its lacking, but the 273 is a sharp looking engine lol

Okay, I'm Game! What do you need to avoid when you swap over to a four barrel?

 

[toolmanmike]

No expert here, and although the 273 has been super reliable we didnt have the performance we thought we would. I wont say what to do or to avoid(no expert). Car is a 67 S, we got original block and intake.(no commando pistons)
We also got another complete 273 that started life as a 2bl.
Heres what we did..
Comp cams and lifters 270-s( too big).
Comp dbl timing chain and gears.
New Eddy 1405(or6) carb.
We left original 323 SG in, and we had 2 torque converters. To be honest both unknown.
That's basically it. 2bl pistons, too big of a cam, unknown tc and 323 gears.
Smaller cam, bigger gears and a new known tc would have made a world of difference. Also commando pistons are very expensive. New landed at my door would be approx $1000.
I'm done sinking $$ in the 273, I dont regret it cuz Dad n I had a blast building it together with a ton of help from fabo.
BUT how much engineering went into the Ddart 273...a lot. And how much hp did they get? I dont think over 300hp?
A different small block is on the stand waiting for me to finish it up.
Its lacking, but the 273 is a sharp looking engine lol


View attachment 1715382485

Basic hot rodding went into the D Dart. They were available to order and components over the parts counter. It was all about drag racing. The HP 273 already had .86 horsepower/cubic inch. Better than most engines of that day. It was a newly redesigned engine for the small cars. The Poly wouldn't fit in the small economy car like the Dart or Valiant back in 63 when those cars were introduced and the 273 V8 didn't become available until 64. The 4 barrel wasn't available until 65 and the 318 replaced it in 67 in the big cars and 68 in the A bodies. Remember, the 318 when it came out had 5 hp. less than the HP273'. More torque of course but less horsepower.

 

[toolmanmike]

No expert here, and although the 273 has been super reliable we didnt have the performance we thought we would. I wont say what to do or to avoid(no expert). Car is a 67 S, we got original block and intake.(no commando pistons)
We also got another complete 273 that started life as a 2bl.
Heres what we did..
Comp cams and lifters 270-s( too big).
Comp dbl timing chain and gears.
New Eddy 1405(or6) carb.
We left original 323 SG in, and we had 2 torque converters. To be honest both unknown.
That's basically it. 2bl pistons, too big of a cam, unknown tc and 323 gears.
Smaller cam, bigger gears and a new known tc would have made a world of difference. Also commando pistons are very expensive. New landed at my door would be approx $1000.
I'm done sinking $$ in the 273, I dont regret it cuz Dad n I had a blast building it together with a ton of help from fabo.
BUT how much engineering went into the Ddart 273...a lot. And how much hp did they get? I dont think over 300hp?
A different small block is on the stand waiting for me to finish it up.
Its lacking, but the 273 is a sharp looking engine lol


View attachment 1715382485

Egge L2222 pistons for the HP 273 are $421 a set. Piston Set

 

[4spdragtop]

Have prices dropped? I thought they were around $600 US which is over 8 in Canuck bucks. Then shipping. At that price about $650 + broker fees in our $$.

Egge L2222 pistons for the HP 273 are $421 a set. Piston Set

 

[Mattax]

Hah, I should have been careful in doubting you. The 66 FSM would trump the 68 Motors Manual in my mind. Do you have a 72 or 73 FSM? Now I'm curious what plugs they specify for the low compression 340's.

1973 Dodge Chassis manual

 

[Mattax]

Hey all, looking for some advice! I have a 67 Dart GT running a 273 with an Edelbrock 1404 500 cfm. (Not sure on cam or engine internals, as modification from a 2bbl was done by a previous owner.) Car is running kinda hot (mainly when stopped in traffic), stalls sometimes on acceleration from a stop, and seems overall anemic in performance. Mechanic said the carb may be bad, and engine overall is a bit "tired" (car had sat non-running for almost 5 years before I got it.)

Has had new water pump, radiator, thermostat, 6 blade steel fan put in, shroud, and system flushed...all that helped, but still running a bit warm.

So, does this sound like a carb replacement issue? (Looking at about $350 to get a new 1404.) And if so, should I go with another 1404, or something else? If a 1404, should I go with a manual or vacuum choke, and mechanical or vacuum secondaries?

Also, any other advice for getting some more power out of it on a shoestring budget? Running gear is a 904 auto, new 3.55 gears.

I agree completely with Toolmanmike.
A little spike idling is nothing to worry about. If it continues to climb and doesn't stabilize - then there's a problem. Coolant temperature is in the correct ballpark for operating on hot day.

As far as the hesitation, if you think its carb, then open it up and do a little freshen up. Big things will be to remove any dirt and bad varnish, replace gaskets and any rubber check valves or piston seals that are distorted or deteriorated. Check float setting and you're done. Yes its a little time consuming the first time but you'll do as well or better than a 'rebuilt' carb; and just as good (maybe better) than a new one.

 

[Dana]

If you decide to go with a new carb, I’m pretty sure I have a rebuilt 67 273 AFB on the shelf, pretty sure I replated most of the linkage. Or If you are looking for a thermoquad, I can build to suit, and will beat Summit on price and quality.

 

[Exjouster]

If you decide to go with a new carb, I’m pretty sure I have a rebuilt 67 273 AFB on the shelf, pretty sure I replated most of the linkage. Or If you are looking for a thermoquad, I can build to suit, and will beat Summit on price and quality.

What are you looking for on price for the 67 AFB? That’s a 500 cfm 4bbl, correct?

 

[Wyrmrider]

Or switch to an AVS

 

[toolmanmike]

I have a couple 600's as well. A Edelbrock and a Holley.

 

[toolmanmike]

Hey all, looking for some advice! I have a 67 Dart GT running a 273 with an Edelbrock 1404 500 cfm. (Not sure on cam or engine internals, as modification from a 2bbl was done by a previous owner.) Car is running kinda hot (mainly when stopped in traffic), stalls sometimes on acceleration from a stop, and seems overall anemic in performance. Mechanic said the carb may be bad, and engine overall is a bit "tired" (car had sat non-running for almost 5 years before I got it.)

Has had new water pump, radiator, thermostat, 6 blade steel fan put in, shroud, and system flushed...all that helped, but still running a bit warm.

So, does this sound like a carb replacement issue? (Looking at about $350 to get a new 1404.) And if so, should I go with another 1404, or something else? If a 1404, should I go with a manual or vacuum choke, and mechanical or vacuum secondaries?

Also, any other advice for getting some more power out of it on a shoestring budget? Running gear is a 904 auto, new 3.55 gears.

We need to go back to the OP's original post. We got sidetracked here. He was having what he thought might be a overheating issue caused by the carburetor. I would say wrong on both counts.

 

[Wyrmrider]

overheating, include checking
plugged/ bent exhaust
timing
round up the usual suspects
t stat, corroded impeller, rad etc

 

[toolmanmike]

overheating, include checking
plugged/ bent exhaust
timing
round up the usual suspects
t stat, corroded impeller, rad etc

Radiator cap loosing pressure

 

[Wyrmrider]

why did I not mention that
I was going up the Ridge Route when I overheated
filled up with water and did not get far
Vehicle had two caps
one on the overflow/ in lue of upper tank and one on the rad
one of them had come apart
Ridge route is in the middle of nowhere between LA and Bakersfield
We used to use it to test for Ma Mopar in addition to the "Baker Grade" near Death Valleu
Thank god for AAA and big tow package that paid for tow back to the shop in LA and a car switch for me- made a long hot day

 

[Exjouster]

Radiator cap loosing pressure

Have already replaced the radiator, water pump, hoses, and thermostat. System was flushed. Running a 6 blade mechanical fan with shroud. Timing is at 10 degrees advanced. Have hood to cowl and hood to radiator support seals in place. Radiator cap is new, but will try a different one.

Car had sat for about 5 years before I got it. Carb doesn’t respond much to adjustment screws, and performance is overall poor. Might be some corrosion in the motor?

 

[toolmanmike]

After reading your posts and everyone elses, it doesn't sound like you have a overheating problem. 210° setting in traffic isn't overheating. Water boils at 212° coolant at 220° or so. Every pound of cooling system pressure adds 3° to the boiling point so a 15# cap adds 45°. You shouldn't boil over until it reaches 265° or thereabouts. Try a 180° thermostat and see if it makes a difference. Make sure your timing is set a 10° or so and run with it. Overhaul or replace your carb if it's not working correctly.