dual point distributors

[Topless73Qcode4SPD]

Hello All,

Just a distributor question for the experts out their.

I have a 73 Q code Cleveland. I have been led to believe that the Q code came

from the factory with a dual point distributor. Mine currently has single points.

I have been unable to find much documentation on this and have not been

able to locate a used one to try.

What's the story on this?

Tx in advance

Ray Q.

I guess the question I should also be asking is

Do I need the dual points?

What do I get performance wise.

It would seem that at high RPM there may be some benefit as the points cam is flying by so fast that

a single point setup may start missing firings.

That's just an educated guess on my part though.

Anyone have any theory out there regarding this?

 

[Boss1Ray]

I believe all 351 Cleveland Cobra Jets came with dual point distributors.

Many were replaced with single point distributors and the old ones were lost.

I might have some documentation. They are on ebay but usually pricey.

Ray

 

[FastE]

The "Q"code autos came with a single point distributor. I may be wrong, but I beleive the 4spd cars got the dual point. All the autos were single point for sure. Hope that helps!

 

[Tnfastbk]

Q-code (Cobra-Jet)The Q-code "351 Cobra Jet" version was produced from May 1971 through the 1974 model year. It was a low-compression design that included open-chamber "4V" heads, a special intake manifold, special hi-lift long duration hydraulic camshaft, special valve springs and dampers, a 750 CFM 4300-D Motorcraft Carburetor, dual-point distributor, and 4-bolt main bearing caps. It was rated at 280 bhp (209 kW; 284 PS) for all 1971 applications; 266 hp (198 kW) (SAE net) for 1972 when installed in the Mustang and 248 hp (185 kW) in the Ford Torino and Mercury Montego. The horsepower rating dropped in 1973 to 246 hp (183 kW) for the 4-barrel for the intermediate Fords, and still retained the higher 266 hp (198 kW) rating in the Mustang. The 351 CJ (now referred to simply as the "351 4V") was rated at 255 hp (190 kW) in 1974 and was only installed in the Ford Ranchero, Ford Torino, Mercury Montego and the Mercury Cougar.

 

[c9zx]

The "Q"code autos came with a single point distributor. I may be wrong, but I beleive the 4spd cars got the dual point. All the autos were single point for sure. Hope that helps!

+1. Confirmed in original service manual. Chuck

Hello All,

Just a distributor question for the experts out their.

I have a 73 Q code Cleveland. I have been led to believe that the Q code came

from the factory with a dual point distributor. Mine currently has single points.

I have been unable to find much documentation on this and have not been

able to locate a used one to try.

What's the story on this?

Tx in advance

Ray Q.

One book I have lists 1973, 351 4v, manual transmission having an ID number of D3PE-12127-PA. Service replacement, D3PZ-12127-P. Don't know if that helps any. Chuck

 

[FasTnNefariouS]

Back in the days, dual points were just twice the problem a single points was and so some would just replace with single points.

 

[Topless73Qcode4SPD]

I guess the question I should also be asking is

Do I need the dual points?

What do I get performance wise.

It would seem that at high RPM there may be some benefit as the points cam is flying by so fast that

a single point setup may start missing firings.

That's just an educated guess on my part though.

Anyone have any theory out there regarding this?

 

[1971mach1]

I would just put in Pertronix electronic points. It's MUCH more reliable and you don't

need to adjust or replace points anymore. Plus it all fits under the stock dist cap so nobody can tell.

 

[cobra3073]

My "one owner" '73 351CJ (Q Code) Mach I came from the factory with single points.

In my neck of the woods, the going thing was to replace the single points with a dual point set-up. This is what I did in the form of a Mallory unit. Nowadays, it supposedly makes no sense utilizing this old (points) technology as there are so many much better electronic systems on the market.

As one of the posters indicated and/or inferred, a lot of people are using the Petronix. I am using one of their units in my 472 Grande.

Hope this helps.

BT

 

[Topless73Qcode4SPD]

The Petronix units also come in single or dual point flavors and I plan to convert.

I guess I'll stay on the lookout for an original Ford dual point unit for 73.

Id like to keep the engine looking as original as possible.

Q-code (Cobra-Jet)The Q-code "351 Cobra Jet" version was produced from May 1971 through the 1974 model year. It was a low-compression design that included open-chamber "4V" heads, a special intake manifold, special hi-lift long duration hydraulic camshaft, special valve springs and dampers, a 750 CFM 4300-D Motorcraft Carburetor, dual-point distributor, and 4-bolt main bearing caps. It was rated at 280 bhp (209 kW; 284 PS) for all 1971 applications; 266 hp (198 kW) (SAE net) for 1972 when installed in the Mustang and 248 hp (185 kW) in the Ford Torino and Mercury Montego. The horsepower rating dropped in 1973 to 246 hp (183 kW) for the 4-barrel for the intermediate Fords, and still retained the higher 266 hp (198 kW) rating in the Mustang. The 351 CJ (now referred to simply as the "351 4V") was rated at 255 hp (190 kW) in 1974 and was only installed in the Ford Ranchero, Ford Torino, Mercury Montego and the Mercury Cougar.

Excellent info....

Tx

 

[OMS]

My O2

Out of 85 various 71-3 Mustangs I have had.

Many M and Q codes both autos and 4 speeds I have never had one with a dual point.

Go with the pertronix

Don

 

[71 ramair 4-speed mach 1]

I used to have a 73 Mach 1 Q-code 4-speed and joined a registry out of Canada that catered to the 73 Q cars, and they sent me a letter with some interesting facts in it one of them being that all 4-speed cars came with dual points( I had not opened my dist. up before then I ran right out all excited and was overjoyed to find mine still in place.) autos with single. And the 73 4-speeds were credited with being the lowest 4-speed production in mustang history up to that point.

 

[C_andy460]

My favorite upgrade is a MSD box and coil. These can be used with points or magnetic pick-up and works just as well with either. Any Cleveland is better off with a good high voltage ignition and this is the best bang for the buck. I have used several of these both new and used and they are totally reliable, just don't go welding on your car with one hooked up because that will zap one quick. Welding voltage will back-feed through the ground wire and burn it up.

Andy

 

[OMS]

I used to have a 73 Mach 1 Q-code 4-speed and joined a registry out of Canada that catered to the 73 Q cars, and they sent me a letter with some interesting facts in it one of them being that all 4-speed cars came with dual points( I had not opened my dist. up before then I ran right out all excited and was overjoyed to find mine still in place.) autos with single. And the 73 4-speeds were credited with being the lowest 4-speed production in mustang history up to that point.

I have heard that 73 Q info before, so that might be true.

Out of 71-3 , 4 speed cars, Marti book says

71 = 8420

72 = 3539

73 = 4228

 

[will e]

The advantage of dual points is you can increase your dwell (the time the circuit is closed and the coil is saturating).

Single point:

After a certain rpm (I forget what it is off the top of my head) the time the points are closed is too short to properly saturate the coil. Since it is a mechanical system there are limits to the cam shape, size and the points riding on it. You have to have the connection broken long enough for the coil to spark but closed long enough to saturate the coil. Adjustment is done by setting how far apart the points are while the arm is on the top of a cam lobe. There is a physical limit to how much time you can keep the points closed (dwell angle).

What a dual point does is it sets the points slightly apart, like 8 degrees of dwell. So the first set of points close the circuit 8 or so degrees before the second set of points also closes the circuit. When the first set of points opens up the second set of points are still closed so the circuit is still complete (closed). Finally, the second set of points also open which breaks (opens) the circuit and the coil releases the spark.

Points are a pain. As the arm wears it will impact the ignition timing (actually advances timing since the circuit opens earlier).

I would go with an electronic system. I use the mallory uni-lite. It uses an LED and sensor and is pretty reliable. I don't have any experience with the petriox unit (did I spell that right)??

I did run a mallory dual point for several years. Always going out of adjustment and a pain to adjust. I don't know how the guys with chevys and distributors in the back did it....

 

[Topless73Qcode4SPD]

The advantage of dual points is you can increase your dwell (the time the circuit is closed and the coil is saturating).

Single point:

After a certain rpm (I forget what it is off the top of my head) the time the points are closed is too short to properly saturate the coil. Since it is a mechanical system there are limits to the cam shape, size and the points riding on it. You have to have the connection broken long enough for the coil to spark but closed long enough to saturate the coil. Adjustment is done by setting how far apart the points are while the arm is on the top of a cam lobe. There is a physical limit to how much time you can keep the points closed (dwell angle).

What a dual point does is it sets the points slightly apart, like 8 degrees of dwell. So the first set of points close the circuit 8 or so degrees before the second set of points also closes the circuit. When the first set of points opens up the second set of points are still closed so the circuit is still complete (closed). Finally, the second set of points also open which breaks (opens) the circuit and the coil releases the spark.

Points are a pain. As the arm wears it will impact the ignition timing (actually advances timing since the circuit opens earlier).

I would go with an electronic system. I use the mallory uni-lite. It uses an LED and sensor and is pretty reliable. I don't have any experience with the petriox unit (did I spell that right)??

I did run a mallory dual point for several years. Always going out of adjustment and a pain to adjust. I don't know how the guys with chevys and distributors in the back did it....

This is good stuff.

Tx for taking the time to write it up.

Regards

Ray Q.

Question?

Can I stick the dual point Petronix unit in my single point housing.

Is there a wiring difference?

 

[c9zx]

I believe the pertronix base plate for single and dual points are different. There are two different part numbers for single and dual. There are also 3 different pertronix units (I,II,III). It seems there was a thread on this subject here.

Chuck

 

[Topless73Qcode4SPD]

Well, after looking thru the Petronix thread, maybe I'll just stick with mechanical points for now.

My car's a Sunday driver anyway.

I will look for a dual point unit though.

 

[hyena429]

mine came with dual point..and so did the old blue one we had...both were auto's and original numbers matching 351 cj....i put the old dual point in a box and got a hei for it...i just got tired of adjusting them things..lol..but it did work good.