Not-so-foul 304

[Tom Mandera <tsm1@domain.elided>]

Did a LOT of driving this weekend.. something like 600 miles or so, and 
did a little experimentation.

I went 30 miles @60mph, and filled up, then 30 miles @ 65mph, and then 30 
miles @ 70mph.

If I keep it to 65mph or less, I was averaging 13mpg.  I think on the 
70mph stretch, it was closer to 7mpg.  Problem is, the 70mph stretch also 
included some in-town driving, so I may be off a bit.  

Plugs were not fouled.  Didn't "feel" fouled, didn't run rough, and I was 
13mpg!

Then I got home from Red Lodge, and headed west to Missoula, over the 
pass.. trying to climb in 4th gear at 60mph, the RPMs / mph started 
dropping off, and then I felt the truck lurching some, as the plug 
started fouling...

Took my foot out of it, downshifted to 3rd, and made it easy at 45mph the 
whole way up the hill.  Plugs felt OK, continued on at 65mph the whole 
way to Missoula.

Still 13mpg give or take.

I'm heading back to Missoula next weekend (or maybe I'll test again this 
week).. I'm going to change the oil again before I do another test run, 
and then I'm going to try 70mph and 75mph again.. and see how it goes.

So I'm back around to thinking it's a "load" issue.  70mph must be a 
threshold load condition, just like trying to climb an 8% grade.

I think I'm going to buy some longer vacuum line, and put my vacuum gauge 
in the cab, to see what's happening when I start feeling the motor 
jerking from the plug fouling.

It may come back to being a bad power valve perhaps?  I dunno... I think 
the vacuum gauge may help explain a few things, hopefully.

Then I'll go back and lean the idle mixture and lower the idle speed, and 
figure out why it's starting hard now (seems, no matter what the choke is 
set to, I must floor it, and just crank it over a few tries until it 
spins, and then catches after I release the key).  Then I can work on my 
driving habits as well, and get myself over the 5mpg in town. :-)  (OTOH, 
I don't blame the 5mpg in town on the truck... *smile*)

I also stopped at the local BIG-A and tried to get a new rotor for this 
apparently aftermarket EI on my '72 304.. he couldn't find one, but the 
closest this guy could think of was a 4cyl Chrysler application... with, 
of course, only 4 slots in the ring on the under-side of the rotor, not 
the 8 I need.

I'll try NAPA tomorrow or so, and if that fails, I may be getting a 
Pertronix sooner than I thought..

-Tom