I guess the next question should be- what year ranges can I use? I assume I could use either 240 or 300?

I found an ad for a decent, rebuilt 240 that the seller says came from a 66 mustang. It looks exactly like mine. Then there is another listing from a 65 Mustang- he didn't state the size, but the valve cover looks different (it is wavy on the drivers side side, where mine and the first one for sale is straight).

Also, how new can I go?

 

Dennis Carpenter now carries the 70 Grill inserts.
Grille Insert - RH or LH | Dennis Carpenter Ford Restoration Parts

The only 6 cyl that came out in the 65 & 66 Mustangs would have been a 200, the 64 1/2 that was registered as a 65 would have had a 170.

 

Why headers on a lunk stock 300 hauler? Get a log manifold and be done with it.

 

as mentioned by cougarjohn pull 1 spark plug wire off at a time,if problem is with any rod/piston/pin on that cyl you would hear the difference with wire off

 

Sorry, I had a brain fart. The 66 engine (240) is out of a truck, the 65 is out of a Mustang.

No idea, but I hate 'em. Truck came with them. With the way they are designed, it has to constantly heat soak the starter.

Did that- it got a little more quiet with #5 removed. Then it did the same with #6 removed. All this with Marvel in the engine.

I'm thinking 20-year-old previous owner + headers = drove it like a dragster until the engine complained.

 

That is a possibility. You could pull the motor and rebuild it yourself, that way you know what you have. As for what will go in there and more modern 300 out of a Bronco or F150 is possible.

 

The previous owner of my truck ran it lean, causing the piston to deteriorate. Also I have read the using synthetic oils, and current gas will cause all kinds of issues.

If you have good compression, why not pull the head and see what the pistons look like? Maybe you just need to replace them, instead of a rebuild.

 

Don't buy any used rebuilds off the internet or anywhere else.

You have good oil pressure, good compression. You say that you hear a change when you pluck wires on #5 and #6. So your problem is not in the valve train, not on the top compression ring. probably not on the rod throws or inserts.

Just drive the thing sanely until the Mystery Oil does its work.

I still think your problem is an exhaust leak. The headers make no sense at all on that engine. Sooner or later they will have to go, you know that. So pull them sooner, buy a log, have a shop resurface the mated pair, maybe replace the studs on the exhaust manifold collector, eat the repair on the exhaust system to turn it back to stock.

 

If I remember right the 240 is the same as a 300 externally . I'd find a donor late model F150 with a 300 and drop that in . I had a 94 F150 with the 300 it pulled everything without missing a beat.

 

Psyclops, pal, methinks we should send you a pair of earplugs to take care of the mysterious tap. Or maybe the volume **** on the radio.

Ford inline 6s are unblowable in normal driving.

Semper Fi

 

Got to the bottom of, well, a lot of issues. First, the crank is slightly bent at the flywheel end. Rear bearing is toast. Flywheel is cracked. #6 rod is bent and the piston has a chunk out of the side.

Not sure what this engine went through, but wow.

Found a replacement from a 66 with around 70,000 since rebuild. I've got it mostly installed now, and it sounds MUCH better. I just need to run a new exhaust, since I ditched the headers and went with the manifold that came with the new engine.

 

Holy Moly!... That's a testament to how tough the 240/300 I6 is... to take that kind of damage and continue running strong (except for the noise) is amazing.

 

No kidding! Holy cow. I can only imagine some numb nut dropped a screw or something down the carb. And started the engine. That screw or whatever travelled to #6 cylinder. Then lifted the engine/tranny combo via a jack on the flywheel to remove the pan. If I'm right he's not the sharpest tack on the board.

 

So now I'm having some weird electrical issues. When I first got the new motor hooked up, I had a no crank/no start. It acted like the battery was completely dead (it wasn't). After checking and rechecking everything, it dawned on me that there was no ground wire grounding the body/frame. I assume it worked before because the headers rubbing the frame in three places provided a ground path.

So I got everything properly grounded and everything worked fine for two whole days. But now all of a sudden, when I hook up the battery negative, the regulator clicks. If you hit the key, it's back to acting like a slow-crank dead battery. Release the key from the start position and it keeps trying to crank. Undo the negative to kill it, touch the negative again and it tries to (slowly) crank even with the key not in it, and a good spark flies from the negative when you touch it.

Let it sit for about an hour, and it goes back to regulator clicking, but no crank until you try- then back to a constant crank scenario until you let it sit again.

Maybe I've got my brain wrapped around the new stuff and I'm missing the obvious. But what gets me is everything worked perfect for 2 days. And it's not like there are a lot of wires on this thing.

Any ideas?

 

Did any of the wires on the starter solinoid get switched around?