Hello,
I've decided to swap the engine out on my 82 F100 flairside. It currently has an engine from a 76 in it that a PO swapped (4.9 inline 6). I would like to replace it with another inline 6, what year models will be the most straight forward? I've seen a few 88/89 trucks around my price range with the 300 6 in them, but I'm not sure about the ease of dropping them in or what modifications need to take place. I'm willing to do some mods to get it back running good but would like to keep it as simple as I can. I would even consider just a bed swap but so far that hasn't been an option. Looking to stay around $500.

 

For the most part, you have carb and EFI. EFI started in '87. The mounting and fitment of the engines would be the same. It's just a matter of whether you want to convert to EFI or not.

Otherwise, I believe as far as fitment goes, the shape of the oil pan is where you'll run into differences, depending on if it's a mid or rear sump, etc.

 

Why do you want to swap the engine out?

The main thing to watch out for with the 87+ 300's is they don't have the opening in the blocks for the mechanical fuel pumps. They have a fast burn combustion chamber. Which will require an adjustment to the timing advance in the distributor ( which also needs to be changed out ) if you want to convert one to a carb. But they do have the benefit of a serpentine accessory belt drive set up and the dual exhaust manifolds.

If you are looking for an engine basically stick with any 300 from 67-86. I try to avoid the 65-66 ones because of the different thrust main bearing.

Like AbandonedBronco the 79 and older 2wd trucks will have a center sump oil pan. But any out of a 65-79 4x4 should have a rear sump pan and any 80-86 will have the rear sump pan needed for your truck.

 

I'm swapping the engine because I blew my head gasket and had to keep driving it for around 9 months till I could afford to get another vehicle. The head ended up so warped the machinist was going to have to take over 40 thousandths off to true it up. But he found it had been so hot so much it actually cracked in a few places and was missing a giant chunk from inside the exhaust port, that also ended up cracking the exhaust manifold in half with a giant chunk gone.

So by the time I replaced both those parts the cost would put me right around what the used engines run around me. The truck still ran and drove when I pulled the head, but would overheat or sometimes hydrolock after about 15 minutes of of driving. So Im assuming the lower end is probably pretty rough, most people think it shouldn't even still run at all.

I'm not opposed to an efi conversion but may be a little more work than I was looking for. I've done some auto work but not a lot. I get the basic concepts and have the ability to learn, just not the know-how and specifics yet.

 

Wow, another testament to the robustness of the 300. . You can probably squeeze another year or two out of it yet!

But yeah, it sounds like it's on its last legs. When you mix antifreeze and oil, it turns into a low grade acid that eats up your bearings, which is usually why you don't want to drive on it. It'll also wash the oil off of your rings, which will burn them up too. Basically, it accelerates the wear and tear on your engine by 100 fold, which is why you usually want to just park it and not move it until a head gasket is replaced.

As for a replacement engine, if you don't want to mess with it too much, just find a carb'd 300 out of 70s or 80s truck and throw it in. Even if it's used, it'll be way better than what you have. I lucked out and found one on Craigslist for $50. Spent another $75 on gaskets and fresh oil and swapped it in and drove it for another few years. It had almost perfect compression. It's just a matter of finding one.