449 motor issues

[BeatersRus]

so i have managed to gather most of what i need to upgrade this car,but
the 440 in it is giving me issues.
first it was various electrical wiring,ballast,coil,points,etc etc.
and then carb took a dump and now new carb and finally got it right,
but now it cranks slower than snails racing uphill.
and it killed a starter/which was pretty much toast anyways im thinking.

i did a compression test,all my cylinders are at 130lbs.
it did get hot once,and i shut it off/last week.
fires right up if everythings working,and runs fine,doesnt seem to get hot?,but

i dont like the way the compression test went and heres why.
reading goes to 130,and then Rapidly falls back to around 90 once i stop cranking...
rings or valves? or ??
thoughts?

edit: motor info 1976 440 unknown internals.
ran good and did Not show any blowby.

 

[BeepBeepRR]

Could be the valve seats. And or could be rings. Which you said no blow by, I would think the heads needs some work. But there are other guys here that are smarter than I. It stands to reason if the valves aren't seating well, that could cause rapid leak down.

 

[wagonman]

Well here are my 2 cents. At 130 compression it should spin over with ease. On the bleeding back down to 90 psi I would think it is the gauge not sealing. Like the schrader valve is leaking in the hose. How hot did it get? sounds like a leak down test is in order. Get it up to temp yank all the plugs, throttle wide open and test compression if not done this way before. Then squirt a couple of pumps of oil in the cylinders and retest. Unknown internals is kind of a crap shoot. 130 sounds low to me. The gauge should hold regardless of engine condition.

 

[wagonman]

Google running compression test. Alldata has a good read to give you some more info. Ya got to have a quality tester that seals and can give repeatable readings.

 

[PRND21]

If the pressure drops back after you stop cranking the check valve (schrader valve) is in your compression tester is leaking.

 

[threewood]

Issue I ran into with slow cranking....the repop positive (+) cable clamp that is molded with the wire was shitty and melted creating a bad connection. I was able to pull the red wire right out of the end. So I used a replacement terminal clamp from Autozone and no more issues

 

[eric383]

In 1976 the compression ratio was pretty low from the factory and age and wear will affect your reading. If you have close to 130 on all 8 cylinders and it is in the car and sounds ok just use it for now until you have either the time or money to rebuild it. Just my 2 cents worth.