I took the old Mercury out yesterday because it has been a month or so since I have driven it. I made a 3 mile trip to Sam's Club to pick up a few things and she ran sweet as usual on the way there. When it starting as I was leaving the store I noticed it had a miss that wouldn't go away. At a traffic light I noticed the sweet smell of antifreeze accompanied by a large but quickly dissipating cloud of white steam from the left side when leaving the stoplight. I'm glad I was only running a local errand and not on a pleasure cruise. Upon arrival at home and in the garage I noticed that the oil is still clean oil and the antifreeze is clean but about 6" from full - so I guess I got really lucky and am only leaking coolant into the combustion chamber? I bet there's a super clean piston on the left side of the engine, though! After she cooled down I started draining the radiator.
I've had this old Merc for 16 years and I believe this 429 is original so I guess it's about time for these things to happen.

 

Beautiful car, Howard. I would guess you are right about the head gasket.

 

Had a similar problem years ago but mine turned out to be a cracked head. Hopefully, yours is only a head gasket...

 

The BBF is a stout engine, I would place my bet on the gasket. The first thing I would do is pressurize the cooling system and see if it holds pressure...my guess is that it won't. If it does then I would bring the engine up to temp and try again. From the sounds of it, the engine had a chance to come to temp on your short trip and then to rise while parked. This could have been when the gasket decided to go. Not all gasket breaks are between the cooling jacket and the oil passages...BUT, with time and repeated usage they WILL find that path. You are fortunate to have found it early. I can see by the condition of your Merc that it is given good care. Good luck with your top end repair...this might be the perfect time for a valve job and a set of hardened seats.

 

Thanks for the replies, guys. I have wanted to do a rebuild on this one for a while, but I was hoping to choose when. It does seem a good time to take care of both heads while I have that beast of an intake off.

 

In continuing this off-topic thread I thought I'd share an update. The head gasket was indeed the offending issue on the 429 in the Mercury. I first removed the heads and had my machine shop guy rework them.
We replaced all the valves and installed hardened seats for the exhaust valves. It took him a couple of weeks to complete them and in that time I made the decision to go all in and freshen up the bottom end too. I pulled the lower half and hauled it to him. The engine was in good shape for its age- it got a crank polish, new wear internals, a cam upgrade and we're going with roller rockers with 3/8" pushrods. I have a new Holley 4160 to go on it after I set it back in the car. I am happy to report that it is in the final phase of assembly and I'll pick it up this week!

On a side note, this is the same machine shop that has been a little slow on my 226 truck engine, but I can report that it is also ready to go back together. I can only handle one engine install at a time!

Here are a few shots of the 429 before and during.

 

That is a pretty engine, all freshened up.

 

I don't have much news to report about my old truck, so I'll run this thread for a day or two more until I get this project completed.
Over the weekend and with a few days off I have managed to get the fresh 429 ready to set into the engine bay. I have mounted all the belt driven components but I will be removing the a/c compressor prior to installing the engine because it affects the balance way too much when lifting the engine. I don't believe a stick of dynamite would blow that a/c compressor off this engine! Valve covers shown are temporary until the engine is set. I am going back with the original repainted "Power by Ford" covers.

 

And while still off topic, I'm happy to report that this Mercury project is pretty much complete. She's running again and sounds better and stronger than ever! I have the stock air cleaner freshened up as well and waiting on the decal to arrive.
Now I can get back to the truck crawl.

 

Great to see your progress

 

Wow! Looks amazing and I'll bet it's a torque monster. I'm surprised you didn't sneak a 460 crank and pistons in.......or did you?

 

On your first post of this thread you said "old Mercury." What year is the car? My guess would be about 72 - 75. It's certainly a beautiful car. Must ride like being on a fluffy, swift cloud. Now a dumb question. . . . did FoMoCo have two 429 engines? I think yours is different than the Boss 429 that came out in limited numbers to homologate the engine for NASCAR. I ask this based on a previous reply about using a crankshaft and other parts from a 460 engine.

 

So how come the 429 didn;t slip into the truck

 

This Mercury is a 1969. You are correct about the ride, and the steering is so effortless it's almost as if the steering shaft isn't connected to anything on the other side of the firewall. Ford had several versions of the 429 with the Boss being the most known and rare. There was also a 429 Cobra Jet and a 429 Super Cobra Jet. Both had upgrades but neither had heads like the Boss. The 429 in both this '69 and the '70 models share engine mounts and water pumps with the Boss and other 429s from those two years, which eliminates the possibility of buying an off-the-shelf rebuilt pump. I had to send mine to Egge in CA for a rebuild.
The 429 and 460 share the same block- the difference is the stroke. As was mentioned, I could've replaced the stock 429 crank with one from a 460 to add some cubes, but this old Merc has all it needs- especially now.

 

The thought did cross my mind, and I have a spare 429 of the same vintage in the shed. My preference all along has been to put the truck back very close to stock. I know this will limit the speed of travel and I may change my mind after it's complete, but I want to drive it stock for a while.