OK, My truck has been missing a bit under load. So I pulled the plugs tonight. It was pretty obvious I have a problem. #4 is bad and that scares me. #4 and #8 were on very tight.
Here is a picture of them. I would welcome suggestions. I have about 1500 miles on these plugs. BJ and I regapped them this summer while we were in Branson. I haven't checked gap yet on these now.

 

There's a chance you don't have a problem... Now that you've got the engine running pretty well, and are driving it longer distances, it's going to throw off some of the accumulated gunk that was built up in there. Before you get too excited, try a fresh set of plugs, or clean those up really well, and run it some more.

If it isn't that, you have some valve stem seals or rings that aren't in great shape. The rest of them look pretty good.

 

What Ross said. I would clean them good and reinstall. Also, keep track of what plugs were in what location and install them in different locations. Run the truck a couple thousand miles and recheck. Expect spark plugs to look like crap in cold weather operation where the choke is used a lot and the engine fails to reach operating temps.
Edit: Chances are the gap will be as when you gapped them........Unless they were dropped, that is.

 

Thanks for the input guys. That relieves me a little bit. I will get them cleaned up and put back in.....Well...sometime soon.
I hadn't thought about swapping locations, good idea.
Now I have an excuse to go for a long drive. I'm sure I will be much more comfortable with 8 cylinders instead of the 7 it looks like I've been running.

Ray, you know me too well. But in this instance I haven't dropped them.

 

It looks to me as though your number 4 is not gapped properly as it is rare for even a cylinder using oil to accumulate deposits on the actual firing surface .

 

haven't dropped them.... Yet!

Joe, didn't you have your engine rebuilt?

 

We will see what the gap is when I clean them up. When BJ and I gapped them this summer, there was one that was way too close. I don't recall if it was #4 or not. But we put them in gapped properly.

Yet! exactly.
No, I didn't have it rebuilt. It was rebuilt back in the late 60's and I was told only had about 30,000 miles on it. But sitting for 40+ years can do all sorts of things with it.

 

I know a good engine rebuilder Joe Might check #4 wire also. Could be a bad connection or might be broken.

By the way, did you get totally moved to your in-laws place yet?

 

Joe,
Has the miss been there all along or did it just start? I don’t recall which plug gap was too close either.
The above recommendations are spot on. Do you have a compression tester (Gauge)? I’m pretty sure you can rent them at the Big Box Auto Parts Stores. I must say all but #4 look pretty good.
If your compression in #4 is good, you can change the valve seal with an adapter (in the sparkplug hole), a good compressor and something to compress the valve spring while still installed on the block. Probably best to change them all if you need to change one. 40 year old seals can be pretty iffy in a Effie.

 

Just from a larger view the back 4 plugs seem to be running cold. Ross may be correct about running it at highway speed more. I'd be suspicious of the plug wires but with a Y-block with the distributor in the rear so those are the shorter wires. With the next set of plugs I would watch for that pattern.

 

Dave, I might just need a rebuild at some point. Gotta save the pennies.
We haven't moved in yet. Nelson has been up at the farm since 11/28. He will be back on Thursday. We have been staying at our house and not planning much on the move. Things will really pick up on that front after Sam goes to school on Jan 8th.

I got a compression tester from O'Reilly's. The guy warned me that he has had a couple of bad testers. Well, I was not happy with what I got for readings.

1 - 90 5- 90
2 - 85 6 - 75
3 - 90 7 - 75
4 - 50 8 - 95

Now the engine has not been run for a week. I would bet if I start it up and get it warm, that would help. But #4 being almost half of all the others is a bit worrisome.

Here are numbers I had the last time I checked them (2012) Adjusting valve lash and putting a little oil in and running it a bit really helped. I did just adjust my valve lash the other day.
https://www.ford-trucks.com/forums/1...l#post11989778

I need to research valve seats. I actually probably need to pull the rocker arms and clean those again. (The right side doesn't seem to oil as good as the left.) I could pull the heads as well and check everything out. I won't do that for a while though.

By the way. It is so much easier doing that stuff with the body off. It was a pain getting the compression tester in.

 

Thanks for the update Joe. At least you have the convenience of taking your time. Our last move, we closed on our house and bought the one we live in now the same day. The buyers were not very cooperative so we had to move the same day

Thanks for the advise. I need to do a compression test before I put my front clip back on.

 

Any chance you didn't adjust the valves on #4 correctly? #4 used to be one of your better cylinders.

 

Joe, oh I hope your engine doesn't need a rebuild or any major work! Especially after all the work you've done to get it on the road. Fingers crossed.

 

I was thinking about that. It would be good to double check my work. But the crud on the plug was there before the adjustment. Well, I'm pretty sure. I only drove it about 5 miles after the last adjustment.