Cylinder compression-power
 

If cylinder compression is relatively decent (160) for its age but the heads have rusty ports, how badly does that decrease power?
7/8 of my cylinders were 160 or so and 1/8 was 105 (previous thread).
Two head ports near rear of block were rusty to the point the machinist said there wasn’t much flow at all. He figured two intake valves were closed and water sat in somehow for a very long time.
After heads are back on can I expect a decent boost in performance even if it doesn’t boost cylinder compression above 160?
I assume the one at 105 should go up but the two at 160 were choked off a bit from flow.

The ports shouldn't effect compression either way. Compression is about what happens in the cylinder when the valves are completely closed. When the valves are closed, the ports are out of the area of concern. What you had done to the heads that will get the compression back up in that bad cylinder is the replacement of the bad valves. When they seal you get proper compression and yeah, I would expect it to run a lot better.

That makes sense.

Can I expect anymore power from the heads being rebuilt in addition to that cylinder regaining its compression?

I'm sure you will have more power Mike...whether you'll feel it in the seat of your pants, I don't know. Since you had good compression on all but the one cylinder, sounds like all the valves were sealing but the one pair in spite of the fact that the valve heads were just about to part ways with the stems.
Why, did it seem particularly weak before you had the work done? Is that why you started checking things out?

No i really never pushed it hard. It started with the passenger side of the motor smoking., followed by compression test. Then stopped smoking after rocker fix but not all compression came back.

It was just luck that I went forward with chancing a valve job...trial and error I guess.