So I have 73 f100 that is having oil pressure problems while running. Basically is starts at 45 and drops to 15 when I am idling after an hr. When I hit the gas it bumps up to about 30. I think I am also seeing some blowby on the passenger side pcv valve system. It has a numbers matching original engine in it. I would like it to be something reliable enough my wife could drive it.

I read that 73 happened to be the year where the 302 performance tanked so I was also wondering about some performance upgrades. 147 hp for a 1/2 ton truck seems incredibly low.

I don't know whether I should invest in rebuilding the block or replacing the engine with a reman'ed one. What do you guys think. It is a 4x2 long bed Explorer trim if that means anything you any of you. It has a c4 3 speed auto transmission.

 

Having the original engine really doesn't add to the value of these trucks, especially one that's worn out.
You can rebuild the engine to stock specs, rebuild it and do some performance mods or go with a crate motor or anywhere in between, the choice is yours.
The 302 is well known and performance mods are easy. You could also install a 351W if you wanted more cubic inches.

P.S. I've got a '73 F100 2WD Explorer long bed myself, only it's a 390/C6, originally a 360.

 

Oops! Double post.

 

I'm with Mike on this one. The choice is really yours.

There are plenty of options for engines out there.

AFR Heads
Shorty Headers
Edelbrock Intake
Custom Cam

But be warned... with an upgraded engine, you should look into your trans as well.

The c4 would be a great transmission to rebuild for some really really light duty towing or just as a daily driver. Some folks use the C4 in race applications, but that's big $$$$ to do it.

There is plenty of literature out there (and even videos) on how to rebuild transmissions, rear diffs, etc.

Check out this C4 video. It's fantastic and well-known on this site to be one of the best resources.
Bad Shoe Productions How To Video Series - Ford Transmissions & Rears

I used a similar video from Ken (above link), but for a C6 rebuild.

 

There are also small block C6's out there. Not as common as the C4 but not too hard to find.
The C6 is probably the best automatic trans that Ford ever built and it can take anything a small block can throw at it.

 

I would do a compression check on the motor you have in it before giving up on it because of oil pressure issues .. Before next oil change put a quart of ATF in with the oil (take a quart of oil out if needed but don't exceed the full mark) run it for 15-20 minutes then change the oil and then do a compression check .. Report back with results ..

 

Yes it certainly is the best trans (C6).

I can't wait to see how the one I rebuilt performs... Still have yet to choose my torque converter though.

 

Unfortunately, I just did the oil change with that trick. I even put in a can of engine restore but it didn't do anything after the engine heated up.

 

So now do the compression check .. Unless of course you just want a fresh motor .. How many miles are on the motor?

 

On the OP... 15 psi at hot idle is not really bad as long as it comes while running. The idiot light normally would not come on until around 7 psi. Agree its not ideal but not awful either. Some of these trucks have gone a long time with near zero showing at idle. Heavier oil like 14W40 or 20W50 may help while you decide what to do with it.