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Discussion Starter #1
I've personally gotten to a wits end on this. So much that I'm seriously summoning the Car Gods and Gurus for some help on this one.

Vehicle: 1986 Ford Mustang GT Convertible; 351W swap (1974 Ford Galaxie 500 block)

She's a beautiful "Frankenstein" of parts from too many different years.

Short Story: last summer, the throttle cable got stuck and the carb "got away" from me. She idled high at about 3500/4000 RPM for a little longer than is good. It's a semi-newer rebuild that seems to be just a swap of rings, bearings, and the like. Motor is strong; block is solid; internals are older/forged styles.

When the motor "got away", I definitely blew out a head gasket. Coolant in the oil, cylinders, and she blew white smoke when I was touching her down. The internal temperature was "warm", but I was running the fan and the electric water pump. Coolant gauge never said above 250/260 degrees.

Changed out the head gasket (twice). Changed out the intake gasket three times, even using "performance" versions. I read somewhere that these intake gaskets for old 351W can be a pain in the you know what.

My issue is that coolant pulls into the #5 Cylinder VERY BAD so much that it bogs the firing order and dumps coolant out the exhaust.

In changing the intake gasket, I've also had this issue on the #1 cylinder because I've changed the intake gaskets a few times already. Talk about a bad time when you're adding coolant for your startup and it starts to pour out of the mid-pipe manifold area, under the vehicle.

I'm not finding any coolant in the oil. Oil seems clean.

The Heads stock as far as I can tell. The intake is an aftermarket Edelbrock Victor Jr. OLD hardware. I've noticed some bad scoring on the bottom of the intake and top of the heads on the mating surface between head-and-intake. It's pretty bad.

Without coolant? She fires up just fine, runs and idles good, and has no other issues. I obviously can't keep a motor running too long without coolant.

I've been at this for a few months trying to figure out what went wrong.

I have inspected the block, cylinder walls, heads, and mating surfaces between the head-and-block for any cracks, breaks, or otherwise. I've seen none. Again, engine was warm and running solid when I blew the head gasket and the motor "got away".

Last attempt at a startup had water (I'm done using coolant until I fix this) leaking out the exhaust pipe by the #5 cylinder, down the outside of the block, and out the exhaust.

Help?
 

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Sounds like you have a warped head, I would verifie that the heads and block are flat including the intake side of the heads. The intake must be something you bought used in that the manifold could have been machined to fit a certain block head combanation there for it will not fit yours.
 

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My issue is that coolant pulls into the #5 Cylinder VERY BAD so much that it bogs the firing order and dumps coolant out the exhaust.

Last attempt at a startup had water (I'm done using coolant until I fix this) leaking out the exhaust pipe by the #5 cylinder, down the outside of the block, and out the exhaust.

Help?
So, coolant is leaking both into the cylinder... AND down the outside of the block?

If that's the case, I'd probably replace the intake with one I knew was good... and see if that cures it. Do you have the stock intake laying around to test? I suspect the intake since it's only the front cylinders you are having problems with, and that's where the water passage is.

Anyway, that's what I would test first. Plus, it's the cheapest.

Good Luck
 

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Discussion Starter #4
Thanks, Iowan. As I'm still a journeyman mechanic: How would I confirm that the head is warped? Is this something I need a machine shop for?

The motor was bought off Craigslist and had the intake already attached when I purchased it. I slapped the carb up to it.

Until the motor "got away" from me? I didn't have any leak issues.

A warp definitely explains that possibility.
 

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Discussion Starter #5
Thanks, Mike.

The coolant leaking outside the block only happened once when I think I totally missed the proper installation of an intake gasket.

I have been considering a new intake and think it may just solve my problem.

The truth is: I've been brought to such a point where I think a replacement on both the heads and the intake is necessary.

Finances are a little too tight for purchasing a new set of heads.

I may need to junkyard dog some replacement heads from similar models that will one-to-one swap so I can keep costs low.
 

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Pull the heads and run a strait edge across them, a machine shop can do this for you also. If they are warped its probabal that they can be shaved true again. The intake is another thing, it is possible that the bottom can be cut to help it sit down farther but if the sides have been cut it could just be time for a new one.
 

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Aluminum heads tend to warp, and cast iron is more likely to crack. Not saying aluminum cannot crack, or iron cannot warp...

If you're lucky, the intake is warped/cracked and is spilling water into the front intake ports on the heads... and swapping it out cures your issues. If you're unlucky, the heads are cracked, and you'll need new ones.

You could pick up a stock intake from the boneyard for $10 as a test. At least, that's what I would do in your position. If that does't fix it, you'll need to pull, and likely replace the heads.

Good Luck
 

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It definitely sounds like you have something going on in number five that a gasket is not fixing.
 

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The coolant passages are real close to the #1 and #5 intake runners on the Vic Jr intake. It is possible that an older intake may have some erosion in the casting that's causing a coolant leak into one of the ports, and you wouldn't be able to see it.

A cheap backyard test to determine if this is the cause would be to remove the intake, tape off the coolant passages going to the heads on both sides, and tape off the thermostat opening. Plug one of the coolant outlets, and use the other one to blow compressed air through. If you hear/feel any air coming out of the plenum of the intake, then you have a leak.

You might get away with using some good, thick tape. Otherwise, you would need to fab up something to cover up the ports.

Good luck figuring it out!
 
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