So my current little project is centered around replacing my exhaust manifold due to a huge leak when I bought it. Now with the manifolds out of the way, I know for sure I'll need to do some sanding or milling on the mani side of the head, but at this point I'm just a few bolts and wires away from being able to pull the motor, so that's what I'm thinking I'll do ( I need to put a new oil pan on it anyway, and I have new motor mounts). I kind of want to go along the milling route and send the head out to be mated with my new mani and using grade 8 studs over using bolts, so that will mean replacing the head gasket. That being said, while I'm in there, are there any other easily fixable common problems, or anything I should be wary of spotting? Or is it worth it to deck these heads or anything to get a few more cheap hp, as I know it's a dog to begin with. Just looking for input. I'm new to these motors, but not new to engines in general. Just looking to fix everything I can for my new winter beater.

 

IMO, it is the best workhorse engine built. Some have gone with later model split exhaust manifolds. Have a look at the Inline Six forum, there are a lot of good folks there like here, with a lot of ideas.
Ford Inline Six, 200, 250, 4.9L / 300 - Ford Truck Enthusiasts Forums

 

I did think long and hard about the two piece manifolds, and ultimately decided on getting another one piece due to being in the north and the carb icing issues that go with the two piece. I had basically just wondered of there were any small pieces that would be an easy fix while the engine is out, but I'll definitely give the sticky a gander.

This 300 was a former plow truck and is in an 85 F250. Originally it had a 351, but just by the oil pan with the dipstick tube I'd say the 300 is from the early 80s. Obviously not looking for power, just something that'll start everytime in the winter.

Again, thank you for pointing the way!

 

While you have the head off, look at the top of the cylinder bores. If there is a large lip at the top of one or more cylinders that catches your fingernail, that means the bores are worn and it may need a rebuild.

Pull one of the main bearing caps and see what the bearings look like.

Pull the oil pump apart and see what it looks like.

Look at the overall cleanliness of the engine. If you have tons of sludge under the valve cover and on top of the head, expect the worst.

 

Thank you for the tips!

I did add a few pictures before I head to the inline 6 forum if it's possible to answer, but what is the plate with the bolts on the driver's side of the block where the orange arrow is pointing? Also, I'm wondering on the manifold side (yes, the leak was huge and the mani was literally missing bolts), but is it more common to sand these up with a block, or better to have them milled?

 

The side cover is access to the lifters that move by the cam. The lifters move push rods that moves rockers under the valve cover.


As for the head & manifold matting face it would be best if it could be machined flat again but............
If you don't want to remove the head, might do a valve job when off ($$), I would clean up the face and as you said a block with say 220 sand paper and see how bad it may be. If not too bad I would use new manifold gaskets and all the bolts and call it done.


As I hinted if head is off and depending on miles on motor may want to do a valve job to the head. But know now that the valve seal better it may put more pressure on the pistons & rings and ??? so talking a full rebuild.


Me I would clean it, check that it is flat and put it back together.
Dave ----

 

What is wrong with the surfaces in the above picture? If it's just a little dirt and crud, just get a wire brush on the end of a drill and clean it up. Your new gaskets will seal to it. If you clean it up and then put a straight edge on it and you have a big gap under the straight edge, then you might have a problem.

 

I've never done a manifold like this, so I'll definitely try cleaning it up first. I only thought about doing the head gasket and pulling the head since it will be easy to access at the time.

 

Sealing the head and the manifolds are no different than any other engine. smooth, planed mating surfaces with proper gaskets. I would however consider removing and re-sealing that side cover.