So I bought a 1976 F-150 super cab with a 390 FE and a 3 speed auto a few weeks ago.

The factory oil pressure gauge showed no oil pressure at idle, so I took the factory oil sender out and screwed in a oil pressure tester

This confirmed my worries......

At operating temp, I have about 10 psi in neutral and about 5 psi in gear.....
Driving around town it only gets up 15-30 psi. (40 if I floor it)
I assume this is way too low to keep running the engine any longer.
So I am looking for a new engine and I need to know what I need to look for in a junkyard

1. Would a 390 from a truck with a manual trans work in my auto truck?
2. What year trucks would have the engine i'm looking for. (Would the bolt pattern be the same?)
3. Is there anything else that I should look for when searching for engines?

Keep in mind that I don't have much knowledge about these old trucks.
Any help would be greatly appreciated.
I have included pictures of the door tags

 

First thing I would do is change the oil with correct wt oil and a new filter and run it. If there are no knocks or rattles, drive it, it will probably run a long time if it is not "beat on.".
Edit: Welcome to the forum.
Edit again: Most likely anything you find in a junkyard is going to need rebuilt, anyway.

 

I had changed the oil a few hours before I tested the oil pressure. I hear a very light tapping coming from the top end but I don't think its too serious

 

That oil pressure is a bit low, but not too far out of range for FE engines. They are fairly notorious for low oil pressure.

 

You figure 10 pounds of oil pressure for every 1000 RPM I believe it is.

 

That is a bit low. But you may not to rebuild the engine. Do a compression/leak down test. As you may just have to replace the bottom end bearings and oil pump.

 

Yea, all the above. Check correct wt. oil. Drive until quits. Rebuild your engine, because yard motor should be rebuilt. If it's your daily driver, pick up a second engine and start rebuild in spare time. Use yours as a core when done. If you want to go high dollar route, go with a new crate motor. What they're doing with some of those now is awesome. I just saw a 366 cu in. "302" crate go into a Ford.

 

Couldn't hurt to drop the pan and look at the bearings. Might just need an oil pump?

 

FE motors went into just about every Ford car, pickup, and truck from 1958 through 1976. Any FE will fit in your truck. They are easy to spot, just note the valve covers that equally cover the head as well as the intake. The drivers side of the block will have "352" cast just below the head near the timing cover on almost every FE out there (very few exceptions).

Check the block casting number of any junkyard motor you find as well as the casting number on the heads (in between to 2/3 and 6/7 spark plugs) and do a little googling. That will tell you a bit about what motor you may have found. To verify you have found a 390, pull the spark plugs and rotate the crank (assuming it's not siezed) to measure the stroke. You can do this by inserting a metal rod, wood dowel, long screwdriver, etc. straight down into the plug hole and marking top center and bottom center of the piston rotation with a sharpie. Measure the distance between your sharpie mark to determine the stroke. Option two is to remove the oil pan and fing the casting marks on the crank. 390 cranks will be marked with a "2U" casting.

As mentioned above, any junkyard FE likely needs a rebuild anyway. If this is something you are interested in, pick up a motor to start a rebuild on now and keep driving your current oil-burner while you work on the new one. Take your time and space out your parts over a few months or a year, makes less of a noticable dent in the finances that way. Do your homework on the motor so you can hopefully find a block worth rebuilding. Good luck!!

 

The VIN numbers on the door and the pillar do not match.
Have the doors been replaced or the cab? A little more research would be recommended.
How about a few pics of the engine.
Ben

 

They do match the door tag is not clear but the vehicle sequence number is the same.

 

Your profile doesn't indicate a location. That might help. You can also join a local FTE chapter which is always a good idea. You might just discover a fellow member local to you who has just what you need.
2X on the JY engines. You already have a decent core so why not have a local reman shop provide you with a like new engine. If you want something with better than stock HP, there are lots of options there too. A little Googling will go a long way.

 

The engine code on the door looks like an H and the pillar engine code is definitely an M. What do they look like to you?
Ben

 

Looks like M in both spots. It's a very "H-ish" M but an M all the same.

 

The Aluminum tags are notorious for mis stamps and stamping errors, the biggie is the sequence number is the same on both. And only one dentside truck would have that B54022 sequence number.
As for the engine codes M is a 390 4bbl and H is 390 2bbl. So either way it is 390. So someone punched the wrong 390 code for the aluminum tag.
Also the Aluminum tag is stamped for a 1976 as is the certification label.
It is not uncommon to find mistamps and errors on the aluminum tags a good 1/3 of aluminium tags have stamping errors..,