I'm working on my 70 F350 with a 360 and 4spd

she has developed a realy bad miss. If not 2!!

I did an overhual of the top end about a month ago and replaced all gaskets and seals from the headgasket up. I replaced the plugs and wires but not the cap and rotor because they looked as good as new. I have a fear that the intake manifold is cracked at the manifold preheat jurnal/exaust passage.

If anyone has any ideas I'm open to anything. I can't keep running it like this.

I'm going to replace the cap and rotor in the am and maby just throw a stronger coil at it to help the spark burn threw whatever is fouling it out.

 

Do a compression test to identify which cylinders may be dead. Or, while the engine is running, using insulated plug wire pliers, pull plug wires off and on, one by one until you find one that doesn't make a difference hooked up or not.

 

I did the cap and rotor pluss one of my wires wasn't on verry well at the cap and it made a world of difference. I'm going to let it cool and then take a good look at the plugs.

I realy don't want to put any more time into this engine. I havnt touched my 460 since I tore it down.

 

another thing you may want to check is that you are not getting inductive reactance. aka crossfire. anytime you pass electricity through a wire it generates an electromagnetic field around itself. this is why a no contact voltage tester can tell you whether a wire is hot or not, without touching it. if you have 2 of these magnetic fields close enough to each other and parallel to each other they will both **** each other off! and you can get your miss there. be sure to always use spark plug wire separators and in addition to that sometimes the manual will specify that certain wires need to cross each other at some point before they get to the distributor. by crossing each other instead of running parallel to each other it counteracts this crossfire issue.

this may or may not be your problem but i am just throwing it out there.

 

I think it is. I have a blow by problem so I'm blowing oil out the fill cap. The wires on the driver side get soaked in oil so they loose there insulative value. The two plugs in the middle the boots touch and they wil shock the he'll out of you if you touch them. I put a new Cap and rotor on her and cleaned the wires realy well and it almost fixed it. There is still a slite miss from time to time.

I'm also realizing I have a carb problem. It won't run right with the choke in. I need to have it 3/4 closed to get it to run right. I'm new to carbs so I'm not shure what to do or where to start

 

its always a good idea to change the cap and rotor when you change plugs and wires

 

The miss is back and even worse. It started this am on the way to work and it ran like crap on the way home. I don't get it. All is clean and together corectly. I'm going to have to do some seriouse investigation.

 

really bad miss sounds like my ex

 

Your late to the party once again, This time with a bad joke.
Please stay in the NOW, Bringing up these old threads is annoying a lot of people. Please stop!

 

Really Dude? Obviously you are one of those people who enjoys ticking people off.

 

Yes to what the two above have posted about the glibness. This should be a serious place.
Regarding the original problem:
Dave is correct. I will add:
Plug wires are designed with a thickness of insulation and dielectric constant to withstand the voltage needed to arc a .035 gap to ground under compression. Engineers know this stuff. They build in a margin.
If you have a properly functioning secondary ignition system you will not get a shock off any plug wire. The arc will take place in the plug before the wire fails.
You can add all the hot coils you wish to a properly functioning ignition system and thee shall profit naught. It is like lighting a dynamite fuse from a propane torch or a cigarette butt. Either way you get the same result.
You can check a failed plug wire without pulling the wire itself. Use a timing light on each wire to see the flash.
Disconnecting a plug wire to see of the cylinder changes is fraught; the arc will go somewhere when the field on the coil collapses, perhaps back into the primary module. Leaving you walking.
Many millions have been made off of flame coils and the like but I am not aware of any article in Hot Rod or the other journals that have claim that hot coils add horsepower to a functioning system.

Semper Fi

 

This is true with conventional ignition systems but not so true with CD-type ignition systems, such as MSD.

 

Explain and expand.
Data.

 

Ignition Coil - Tech - Terms & Definitions - Hot Rod Magazine

 

I have read the thing through twice and I stand by what I said:
Replacing a stock coil on a properly functioning ignition system will do nothing for you
Give me a technical argument, not a link.