My daily driver is a 64 Valiant convert, 225 4 speed. It has about 131,000 miles on it, and never has been rebuilt. When I got it it had 3 bent pushrods, a carb that had been rebuilt (and broken) by someone who seems to only had a hammer and chisel as tools, and fouled gas line and tank. I repaired all that, replaced the fuel pump and carb, and now it runs great down the road, gets 19 mpg around town! But, it has a terrible sounding miss at idle. I did a compression test, and all cylinders came in around 120 except number one which was much lower (can't remember the reading). Is it possible that I have a valve problem on #1 that seals good enough at speed, but not a idle? Oh yeah, oil didn't up the comperession test number. Thoughts?

Could be either a burnt exhaust valve, or one of the valves is hanging open. Either adjusted to tight or a piece of carbon is hanging it open. Worst case scenario: The rings are so shot that oil has no effect. Been there, done that with my original engine.

Start with a valve lash adjustment, pay close attention to #1 exhaust valve, if it is tighter then .020, you may ahve found your problem.

It is pretty common for SL6 engines to have the valves "tighten up" when using the no lead gas. The valve seat(s) start to recess and that moves the stem upward, taking-up the lash clearance.
DD

My Duster skipped real bad when I got it. Took it to a mechanic and it had two dead cylinders. Turned out to be bad valve guides. The previous owner had run that cheap motor oil you buy from the dollar store through it for almost 5 years. My mechanic told me that it foamed when it got hot and did'nt lubricate any of the valvetrain. Rocker arms, valvesprings, and camshaft were all shot. $1,000 later (which was more than I payed for the car) and it was back on the road. Wound up rebuilding the entire engine with new componets. Runs like a top now.

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2