Decent Running 350 With 30 PSI?

[Upstate]

Ok, I bought a K5 with a '79 350 in it. Pulled the motor yesterday and did a compression test tonight with a screw in tester. Did a dry test and I got reading from 27 lbs to 30 lbs depending on which cylinder that I tested.

27 lbs and runs? Don't smoke, seems to be strong but doesn't crack the throttle either, but it is a '79 so what 8.5 to 1? Starts easy? Yes. Has anyone had a bad tester before? I have had the tester for years, but it looks absolutely perfect. What the hell am I doing wrong?

I am about to put it into a '87 K5, but didn't want to do that if it is ****. Ok, maybe a bad valve, but all cylinders?

 

[bradshawtech]

Describe the procedure that you are using.

If the engine was "pulled", I am guessing you are turning it over by hand during the test?

There are other problems with your plan to put it into the '87....... The intake manifold will not bolt down without alteration. Everything else should be able to bolt up

 

[Upstate]

Describe the procedure that you are using.

If the engine was "pulled", I am guessing you are turning it over by hand during the test?

Correct. Wrench connected to the harmonic balancer bolt and I turn it over by hand.

 

[bradshawtech]

Compression tests should be run with the starter and battery fully charged.

Technically, carb/tbi butterfly held open, all the spark plugs out of engine.

put the starter on if the flexplate is still on it and hook up the battery cables and try again.

You were just not getting enough speed to get a accurate reading.

 

[Upstate]

All plugs are out, flex and starter still on. Carb choke open. I'll try turning it over with the starter.

 

[Upstate]

Ok, 140 dry, 190 with oil.

Main thing is to get the K5 running at sort out the bugs. I will put a different motor in the truck maybe in the Fall.
Thoughts

 

[ryoken]

as long as the cylinder's are within 10% of each other, it's fine...

 

[Upstate]

Yes, within 10%

 

[imiceman44]

Ok, 140 dry, 190 with oil.

Main thing is to get the K5 running at sort out the bugs. I will put a different motor in the truck maybe in the Fall.
Thoughts

140 is pretty good, which explains it running good.
obviously 180 is better which is what my 90k original miles engine did in my 84 truck before I sold it.

 

[Upstate]

140 is pretty good, which explains it running good.
obviously 180 is better which is what my 90k original miles engine did in my 84 truck before I sold it.

This motor is just to work the bugs out for a couple months. So, 140 should work TBI intake?