72 upgrade

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dragonrider

dragonrider

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I have a 72 dart swinger. Planning on switching it over to electronic ignition. And going with the offy 4 barrel intake. Wanting to know what carb set up has seemed to work best for most of you here. I am using this as a daily driver and want better gas mileage and better performance.
 
Thermoquad or Edelbrock for set it and leave it daily driving, and Holley for performance and constant tinkering. :)

There's going to be a few oppinions on this subject.
 
Here's my opinion.
Unless you do some other engine work, bolting a 4bbl onto a slant is kind of pointless.

I've done it and it was a waste of time and money, and it didnt peform noticeably better than it did with a 2bbl. :twocents:
 
holley 390. get it dialed in and enjoy the mpg. if you know what you are doing its not constant. its get it done right the first time and leave it. mine worked flawlessly for a decade.
 
I have never done it, but it is my opinion, a Q-jet should be a good carb for a street slant. I hope to try it next summer, as I now have a street driver slant.
 
Just my IMO, but 4 BBL is not the way I would go at all for what you name; daily driver, mpg, and performance. As said, the engine breathing is not there for a 4 BBL to be used; a 2 BBL is better for general driveability and even the 1 BBL is not being used to full breathing at lower RPM's.

If you want performance improvements, then
- start with a mild cam; if you stay with a torque cam (more lift with a wide lobe angle), then you can keep the mpg OK and still have a good performance improvement at low to middle RPM's with a small carb.
- shave the head .050 or so for an easy CR improvment; the stock CR is just at that point where even a .5 point CR increase will make a big torque difference

For MPG, look seriously in the 4 speed manual with OD that came in the Dart Lites and Feather Dusters. That will give you the best mpg improvements you can get in that car, and yet you will be able to use 1-3 gears for fun. (I drove one for years....28 mpg in the interstate at 65-70 mph wiht a 2.76 rear axle)

I don't live that far from you so when I get my new torque cam in in a few weeks, you can visit and see the difference.
 
nm9stheham said:
Just my IMO, but 4 BBL is not the way I would go at all for what you name; daily driver, mpg, and performance. As said, the engine breathing is not there for a 4 BBL to be used; a 2 BBL is better for general driveability and even the 1 BBL is not being used to full breathing at lower RPM's.

If you want performance improvements, then
- start with a mild cam; if you stay with a torque cam (more lift with a wide lobe angle), then you can keep the mpg OK and still have a good performance improvement at low to middle RPM's with a small carb.
- shave the head .050 or so for an easy CR improvment; the stock CR is just at that point where even a .5 point CR increase will make a big torque difference

For MPG, look seriously in the 4 speed manual with OD that came in the Dart Lites and Feather Dusters. That will give you the best mpg improvements you can get in that car, and yet you will be able to use 1-3 gears for fun. (I drove one for years....28 mpg in the interstate at 65-70 mph wiht a 2.76 rear axle)

I don't live that far from you so when I get my new torque cam in in a few weeks, you can visit and see the difference.
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I agree with everything you said. The only reason I like the idea of a Q-Jet is, Super six setup are going for too much money, in my opinion, and good carbs are hard to find. You can buy a used offie manifold for less then a super six manifold. The Offie can be used with the stock exhaust manifold, so you still have manifold heat. The Q-jet has very small primary barrels (smaller then the super six carter 2bbl), this will allow for good low speed drivability and fuel economy. Granted the secondaries are overkill, but they are "on demand", and will only open the amount needed. It will definatly require tuning.
 
This is a combo that worked for me. Back in 2000,starting with a 67 Dart, I spent $800 on a Clifford intake,Headers and a Holley 390 along with electronic ignition.The Clifford shorty headers were plumbed into a 2 1/2'' Y pipe and 2 1/2'' single exhaust thru a Flowmaster muffler and completed with a 2 1/2'' tailpipe to the rear bumper.The rear axle was 2.93 ratio.No internal mods were done.In stock form the car ran out of steam at about 90 mph. After the bolt ons the car would top out at 115 mph @ 44-4600 rpm. The stock valve springs were done at that rpm. I then went with 340 valve springs installing them with the head on the block and moved up to a Edelbrock 500 carb.This gave me 52-5500 rpm and would peg the speedo at 120 mph.Fun daily driver.I drove this car on several Hot Rod Power Tours and suprised many when they found out it was a lowly 225 slant six.As stated in the begining this is what worked for me,your results may vary.
 
Darter6 said:
This is a combo that worked for me. Back in 2000,starting with a 67 Dart, I spent $800 on a Clifford intake,Headers and a Holley 390 along with electronic ignition.The Clifford shorty headers were plumbed into a 2 1/2'' Y pipe and 2 1/2'' single exhaust thru a Flowmaster muffler and completed with a 2 1/2'' tailpipe to the rear bumper.The rear axle was 2.93 ratio.No internal mods were done.In stock form the car ran out of steam at about 90 mph. After the bolt ons the car would top out at 115 mph @ 44-4600 rpm. The stock valve springs were done at that rpm. I then went with 340 valve springs installing them with the head on the block and moved up to a Edelbrock 500 carb.This gave me 52-5500 rpm and would peg the speedo at 120 mph.Fun daily driver.I drove this car on several Hot Rod Power Tours and suprised many when they found out it was a lowly 225 slant six.As stated in the begining this is what worked for me,your results may vary.
Click to expand...

There are many different combos, that will work. Personally from reading the original post, he is not looking to spend much money, and he is in a colder climate. With a Clifford manifold you must run headers, so you loose manifold heat, unless using a Clifford water heated manifold. I am not a big fan of headers on the street, on a mild motor, especially where salt is used on the roads. They just do not last that long. Dutra duals or a "homemade" split manifold would be better.

If I were looking improve the slant, and could only do one thing, I would mill the head. Best of all worlds, and no down side. Granted it is more work, but not more money, then "bolt-ons".
 
Sounds like somebody need to come up with a way to mill out the stock 1 BBL manifold so it will take a common 2 BBL....I'd be surprised that this has not been done. Also, part of the Super Six setup that seems to be going for big bucks these days is the auto trans kickdown linkage.... another small fab project.

Understood on the Q-jet. I just know from personal experience how the 4 BBL will dissappoint when the breathing is not there; you open up the secondaries and 'meh'... not the kick one expects. At least the OP has the later cam which breathes a bit better than the older stock cam.
 
nm9stheham said:
Sounds like somebody need to come up with a way to mill out the stock 1 BBL manifold so it will take a common 2 BBL....I'd be surprised that this has not been done. Also, part of the Super Six setup that seems to be going for big bucks these days is the auto trans kickdown linkage.... another small fab project.
.
Click to expand...

My 66 Cuda has a modified stock 1 bbl manifold, that I did back in the late 70's. Milled off the carb mount, Cut a 3/8 steel plate to match the 500 cfm Holley 2 bbl. Spray welded the plate to the manifold (side ways carb mount), and then bored down thru the plate and manifold. That carb is not a good choice for a mild street motor. The barrels are too big, for good drivability at lower RPM. The kickdown linkage is no problem. There are a couple of aftermarket cable units out there. It is also simple to make it yourself, from bicycle/motorcycle brake cable parts.
 
Just take off the 500 and put on a 350....that is a well done job.

Mismatch? I ran a 500 cfm Holley 2 BBL on a 1.9 L Opel rally enigne for years......zero torque below 3800 RPM LOL. But no give up even at 8000....
 
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