Well, in general, all showed improvement. The screw-in type gauge is the most reliable type. According to the Ford shop manual, #1 is your "problem child" (along with possibly #4). You could retest them to be sure you got a good reading and/or you could do the add a bit of oil to the cylinder procedure and retest to try to narrow it down to piston rings or valves as the shortfall.

 

Wow all those numbers are bad if they are accurate.

8:1 stock cam and timing set 335 series will blow 125-130psi.


edit: if you are at 9000’ then 110 seems reasonable but still the results are all over the board. Try #1 again with a few drops of oil in the cylinder.

 

What's the basic history of this engine Mac? How many miles and has it been at least a semi-daily driver all this time? Or has it been sitting for a long time?
Lots of engines will show low-ish compression after sitting for extended periods. I'm not talking months though, talking years at least.

Some times in these cases the cure is actually to just drive it. Even if it's just a temporary "cure" it does make a difference. Multiple heating and cooling cycles and changing the oil a couple of times can make a huge difference.
I don't immediately think that 110 at your altitude is way out of line, but I don't remember the formula for altitude compensation. But 105 to 111 in five cylinders, with only one point separating four of them is extremely consistent. The one at 98 is just barely out of the ten percent range too, so not a deal breaker by any means.

I would definitely do the oil test, in case it shows up what you're dealing with. But more than anything else I'd drive it if it's running? And even if it's bad, maybe you'll get lucky and only need a valve job. I've done that before and the engines really woke up!
But hey, it's possible that the engine is at the end of it's life too. The "smog era" engines did not have the best fuel atomization, heating and cooling characteristics, and if it was driven only short distances at a time, may never have gotten up to a good temperature to get rid of moisture and the acids in the oil that causes.

Good luck though. Maybe it'll wake up a bit on it's own before you have to really tear into it.

Paul

 

I have no idea of the engine history. I do know when I changed the oil the first time it was blacker than any oil I've ever seen. Odometer has 9,150 on it. How many times it's been around the block I have no idea. Bought it from a guy in Oregon who only used it on his ranch.

Thanks for all the comments, though. What I wanted to hear (I guess) was that these numbers still pretty much sucked. After rebuilding the front end last summer I had visions of pulling my first engine.... This gives me reason enough to do it this summer.

Thanks again, fellas.

 

Your compression is not that bad. You likely have a burned or sticky valve in the #1. Run some Risolene through it and clean it up good. Then go back to square 1 on your tune and make sure timing etc. is on point.
Headers are cheap and sort of easy to gain about 40 HP over the stock exhaust. Soak the upper bolts religiously before attempting.
If you blew a head gasket you would have a leak of oil or water or a combo going on, or losing water etc. Most of these old dinosaurs have a burned valve or two. Point is, don't assume the worst case yet.
Like a prior poster mentioned, it could just need a valve job. The FE is a tough motor and burned valves/sticky valve fairly are common. You may get lucky.
Rebuilding a motor will get pricey fast! Trust me, my rebuild turned into a stroker build. Rewarding and fun experience to do it yourself...yes, especially dyno day....but oh the pain in the pocket.