Hello and welcome to the club. First try posting in the Powertrain forum, as that is where most of the gear heads hang, second it seemsthat something is dragging- ie too tight, lack of oil on the bearings or something like that, was the oil pressure good? It should not be hard to turn the crank with the plugs out. I can turn mine by hand with everything out. Mine is an '88 350.

 

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Please do not suggest that someone should post the same question in a different section of the forum. Simply report the post and cite that it is in the wrong spot.
A mod will move it to the correct location.
The "gear heads" don't only visit the powertrain section. Many of our members view the "new posts" section to see what questions have been asked. The New posts area covers the entire forum.

Lowellchu9 you can feel free to delete your duplicate post at your discretion.

 

Thanks for the heads-Patrick.

I hope you and other seasoned members can provide some insight.

 

Welcome

Odd the motor won't turn in N with the plugs out. I wonder if it is actually completely in N. Maybe you could start it, then put it in N, then kill it in N so you know there isn't some sort of transmission "drag".

What do you mean you have to have the ignition advanced 20 degrees to get adequate vacuum? You checked the vacuum at idle and it is low? won't boost the power brakes??

In vehicles of that vintage I am always suspicious of the carb and all the complicated vacuum hoses.
I had a `1980 Dodge D-100 318-not a bad truck, but it was born with an off idle stumble.The manufacturers had a very hard time getting their carb setups meet the EPA regulations, and they made really poor power-your 350 might have been rated as low as 150-165 hp hp or so.

No one fooled with the idle jets etc-dead stock jetting?

Compression is good-maybe 150 psi all cylinders? How many miles on the truck?
Luck
Charlie

 

Do you personally have any history with this truck when it was running good, or did you get it this way?

With plugs out the engine should be easy enough to turn by hand on the main pulley or harmonic balancer. Do you know if anyone ever rebuilt the engine itself? Maybe put the wrong thickness main bearings in.

It definitely sounds like your engine is fighting it's own friction, and this is a major loss of your power.
See if you can get any solid info on the history of this engine prior to you getting it.

 

Thank you everyone for the helpful advice. I agree that it may be fighting internal friction.

Although the truck has been in the family since new, my uncle didn't leave us with any records of it.

As such, I will ensure that the transmission is indeed in neutral and try turning it again.

Lastly, thank you for the warm welcome! I am grateful to be able to participate in this friendly forum.

 

Please keep us updated on your progress or anything new you find out.

 

Just guessing here, is there any chance the valve train may have been worked on at one time?
Maybe a new cam, pushrods, rockers, lifters, etc. and the new parts werent the correct size, say pushrods or lifters for a different application?
Or the rockers are tightened down to much?
I say this because I had a similiar problem years ago on a mid 70's 350 that had been rebuilt by the PO, he attempted to hop up the engine but installed parts that werent compatable so it ran terrible until I started doing research and figured out what was wrong.