For everyday use it is the most popular carb size. Go bigger if performance is your only goal.,...jack

 

As to the Duraspark conversion on our 240/300 engines running with the standard Carter YF or Motorcraft carbs - this upgrade does not provide any performance increase, correct? Basically meant to provide a more reliable ignition system, yes?
A step above the Pertronix-type of upgrade?

 

If you're switching from a worn out TFI system yes it's probably more reliable. Definitely more simple, the TFI system has a myriad of wiring and vacuum lines. The performance increases with the DS2 would come from different combination with intakes, carbs, and exhaust. I'm a newbie, all this knowledge is book read from me. I can't say which is a higher performance upgrade between the DS2 and Petronix. I would guess they're pretty close to equal with DS2 parts more readily available. DS2 would be a performance increase over a points distributor.
Hope that helps.

 

I'll say this. My truck started out as a TFI system which I got running back from a terrible state. I then switched to a points system because of the simplicity which should equal reliability. If I had it to do all over again I'd go to DS2 because of all the knowledge on this board dealing with DS2. Or a DUI unit if money was no object.

 

here's a newbie question. Does the wiring harness have to come from a rig with a straight six? Or will any DS2 wiring harness work on my 1986 300-6?

 

Yes, and no. It may work depending on which V-engined harness you get.m That's because the harness has the wires to the temp and oil pressure senders in it, and each engine family has those in a different place. So, one for an M/400, which has the oil pressure sender at the rear of the block would have a long enough wire for the 300 six, but one from a Windsor may not. But, you can shorten or lengthen the wires and make it fit.

Also, the V8 harness has a ground for the tach that tells it the engine will fire 4 times/revolution. So, if you have a tach and put an 8-cylinder harness in your tach will read incorrectly unless you remove that wire.

 

Thanks Gary. Sounds like it will be easier just to get a wire harness from a straight six.

 

If you can get one it is easier. It just plugs and plays. Otherwise you are likely to have to shorten or lengthen a couple of wires.

 

Yes it's just harder to find the harness where I am currently at. But it's still a good option to use the harness from other rigs. Splicing the wires isn't hard. But the tach I might have to figure something else out.

 

Duraspark II reliable yes , my main reason was the feedback carb and all the sensors etc . The computer takes feedback from every sensor and I guess in lay mans terms, readjusts it per spark and fuel. Our old systems (at least mine) was doing bad on fuel mileage. Best swap I have made . Good luckTR

 

Yes the feedback system (TFI) had a ton of sensors and vacuum lines. Any leaks and it can be a nightmare. When it works it works great. I got 17 mpg with a full load of firewood. When there were leaks it could get 8 mpg. And a PITA to troubleshoot.

 

I truly agree . No computer, no problems , currently getting 15,( running 32-11.50x 15 tires). My upgrade was the Cliffords system , weber 38-38 progressive carb, long tube headers, x pipe and a set of magnaflow exhaust (dual).Just installed a electric fuel pump(redline) .This truck has over 600000 miles .TR

 

Wow TR considering the tires, miles on your rig that's good mpg!

 

Yes , I bought this truck new in sept 1984 $9200, had ac no radio 4 speed(granny gear) and bench vinyl seat with sliding rear glass .My work commute once was 48 miles one way , then 55 miles one way. I have pulled boats , over the years and currently have a 24 foot and 6 x12 trailer .I rarely pull tractors , motorcycles and recently pulled a four door 2004 dodge truck(fuel)(pump went out) Crusing at 45 it ran great but its a short wheel base .The airbags help even the load.TR

 

My rig is a 4sp granny. It's hauled some wet cords of firewood lol.