Will a 302 bolt up to a 51 Merc 3sp od trans?

[Solo_909]

Okay let’s do this, if any of you guys want I’d be willing to sell my Merc to you so you can save it. Here’s all the information, please feel free to send me a message and make me an offer.

For sale
Real 1951 Mercury barn find. This Merc is a true California barn find. It came from Watsonville California and was found in the now closed old Marty Franich Ford dealership. This specific Merc belonged to the wife of Marty, the owner of the dealership. It for some reason sat since 1969 but I’m glad it did because the inside is a time capsule. I have paperwork that goes with the car that has the wife’s first and last name on it for al you folks who love the history of cars along with some other really cool stuff such as how to survive an atom bomb attack and old tv advertisement pamphlets.
The good, the car starts right up and runs like a sewing machine. Everything works except the radio and fuel gauge. The floors, rockers, quarter panels, trunk are solid with no rust issues, a true California car.
Here is a list of everything that is brand spanking new with no miles on them.
6.70 Coker Firestone bias ply tires, new master and wheel cylinders, Brake hoses, rebuilt carburetor, Full clutch kit, Gas tank, Fuel sending unit, Radiator, water pumps, thermostats, 4” Lowering blocks for the rear and Aerostar springs for the front, front and rear shocks, Media blasted wheels, Trunk weather strip, and a rebuilt 8BA Flathead.

The not so good, so even though this car runs like a sewing machine it smokes like a chimney. We have put seafoam and mystery oil in the motor to help clear things up but haven’t put enough miles on the car to see if it will work. It may need a rebuild but I’m not sure. The paint is shot but if you’re looking for original then this is perfect. The driver side window is cracked but will still roll up and down without any issues. It needs a new heater core and The new gas tank and radiator have not been installed yet.

[Frank Miller]

You are on track for an easy fix with some work and a few dollars. Even if this is a fordor it is a nice looking car. If it is running good you most likely have a sound engine. For the work of the conversion you could put new rings and bearings and it would probably fix the smoke issue. The bearings are to refresh. Maybe lap the valves. While this is a half ass rebuild the rings are probably just frozen to the pistons but at the point to take them out for that put in new ones. I bet you could do what I said for under 500. Maybe not even paint the motor to leave the patina. If I were closer I would be seriously interested. You have what sounds like a great car with a great history. Good luck.

[Solo_909]

Originally Posted by Frank Miller

You are on track for an easy fix with some work and a few dollars. Even if this is a fordor it is a nice looking car. If it is running good you most likely have a sound engine. For the work of the conversion you could put new rings and bearings and it would probably fix the smoke issue. The bearings are to refresh. Maybe lap the valves. While this is a half ass rebuild the rings are probably just frozen to the pistons but at the point to take them out for that put in new ones. I bet you could do what I said for under 500. Maybe not even paint the motor to leave the patina. If I were closer I would be seriously interested. You have what sounds like a great car with a great history. Good luck.

Thanks I appreciate it. That’s the thing I don’t want to half ass it. This car is for me and the kids so I’m looking for something very dependable that I can do the work once and not have to deal with it again. I appreciate it

[40 Deluxe]

Originally Posted by Solo_909

I have no idea who the heck is building your guys flatheads for that cheap but H&H flathead in SoCal and GoCat are way over 5k for a complete build. My good friend has a rebuilt 302 / C4 combo for 2k so with a radiator and a new wiring harness and some other parts it’s good to go.

"over 5K"? You would be paying more for "sizzle" than "steak"! Or, for "snob appeal"-'My engine was built by XYZ!", said with nose in the air! Find a machine shop that knows flatheads and price out a rebore and valve job. The rest is just basic reassembly no different than an OHV engine (if you use adjustable lifters).
Did your mechanic pull the heads and measure cylinder taper? Did he find that the engine had already been bored to max? Did he find cracks? Was a rod hanging out the side of the block? Just how did he determine that the engine is "toast"?? I suspect that he just didn't want the job!

[JSeery]

It would be interesting to get some feed back on this down the line. The cost numbers being used are way out of line with my experiance.

[Solo_909]

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Originally Posted by 40 Deluxe

"over 5K"? You would be paying more for "sizzle" than "steak"! Or, for "snob appeal"-'My engine was built by XYZ!", said with nose in the air! Find a machine shop that knows flatheads and price out a rebore and valve job. The rest is just basic reassembly no different than an OHV engine (if you use adjustable lifters).
Did your mechanic pull the heads and measure cylinder taper? Did he find that the engine had already been bored to max? Did he find cracks? Was a rod hanging out the side of the block? Just how did he determine that the engine is "toast"?? I suspect that he just didn't want the job!

Yes over 5k. There’s not many flathead builders out there that I know of and the ones I found all gave me around the same price. Yeah it sounds simple but for a guy like me that has never done it before it will be difficult. I’ll hvw to come online and ask questions only to get 42 different answers leaving stuck and not know what the hell to do.

[JSeery]

Not sure asking the question on a flathead site is going to get you a street rod answer. There are a lot of people on this site who have and do build both. I have a lot of experience at both and your numbers don't line up with my years of doing this. Not trying to discourage you, but if you ask a question I like to provide knowledgeable replays. Have you tried posting on the HAMB? There are mostly a lot of folks there that have done this modification and can give you an idea of cost involved.

[4t8v8]

If you think rebuilding a flathead is complicated wait until you do an engine swap. But it's your vehicle so do what you want. You won't be happy with it if you don't.

[Tinker]

Have to agree with 4t8v8.

What kind of compression is the current flathead? Is the flathead really in need of a rebuild?

What do you want out of it? (I know you want it reliable), Drive 400 miles at 80mph?


Or just have a decent shop do the 302 for you.

[Solo_909]

Originally Posted by Tinker

Have to agree with 4t8v8.

What kind of compression is the current flathead? Is the flathead really in need of a rebuild?

What do you want out of it? (I know you want it reliable), Drive 400 miles at 80mph?


Or just have a decent shop do the 302 for you.

Cylinder readings
1. 90
2. 100-115
3. 89-95
4. 85-96
5. 80-90
6. 80-95
7. 70-100
8. 75-100

No idea, just going off what my mechanic said. I don’t know motors so I have to trust he does.

I want to be able to drive during California’s summers and not have to worry that if I shut off the car that it won’t start back up for a while. It would be nice to go to an auto parts store and get something if something brakes or stops working, and yes to be able to drive long distances without having fear If it will make it or not.

It seems here like my request is odd ball but to me having a flathead is very slim and far and few between. I’d say about 90% have a SBC in it here in Ca.

[funrunr]

Well, at least your looking to put a SBF in it. Have you ever read some of the posts made by “Old Henry”? He’s on this forum and he drives his 47 or 48 Ford all over the world and documents it along the way. That Mercury is quite capable of the same. The reasoning doesn’t ad up, if there are other reasons like speed and horse power, well then yes, that is easier and probably cheaper out of the 302 but that Merc engine was stock 125 HP. My 1995 F150 was 150HP stock.

Your compression numbers look ok/good, is your car blowing white smoke or dark gray? Maybe you have a bad head gasket? This might be a really cheap easy fix. My fingers are crossed for you. Good luck no matter what you decide.

[rotorwrench]

My two 1951 Mercury Sport Sedans came from Kansas and New Mexico. Both were built at the Saint Louis, MO, plant in late 1950. It sounds like yours is in much better than both of mine when I started on them. I had to repair and replace rusty rockers, inner rockers, parts of a floor pan, a spare tire well, a door, and a rear quarter panel. It was a lot of work but worth the effort.


The 1949 through 1951 Lincoln Mercury Overhaul Manual is a very good publication. It has all the information needed to rebuild the entire car including the engine. The 8CM & 1CM Mercury engines are right next to the top of the flathead V8 evolution with the 52 & 53 EAC engines being the last of the line. They are 255 CID engines with the 4-inch stroke and have a very good street cam for power, torque, and economy.


Most mechanics that are under 50-years old today have little or no experience on flatheads and they tend to shy away from them. There are special tools that help with tear down of the engine and not everyone has the stuff. I made most of my own tools when I was a kid and have purchased more as time went by. Most are related to the valve in block assemblies. On my first engine, I had machine shops bore the cylinders and do the valves. My first Mercury still has the original valves & springs. Only the worn out stuff needs to be replaced. I used Johnson solid adjustable tappets to make fitting & clearancing the valves easier. I had to have the crank ground too but all the machine work wasn't all that bad in price. New pistons, rings, bearings, gaskets, oil pump, and the followers weren't too bad on the pocket book. I put it together myself so I saved the labor on that.


The carburetor scares a lot of mechanics because they've never seen one like it before. They are a good carb after a person gets to know them. When I was a kid, I had a hard time finding kits for them but now they are much more available. Some kits are better than others though. These Holley 885 carbs add some performance to the 255 and give the engine enough power to pull the car well. The BW type overdrive helps a lot too. The electric overdrive amazes a lot of folks when it's working well.


I'd love to have another 51 Mercury but I'm still looking for a 6 passenger coupe in good condition so I'm all set on Sport Sedans. One will likely have to go before I start on another one. It's hard to let one go for me. These cars are top of the 8BA block based vehicles in my book. You should easily find a buyer if you decide to sell.


If it's blue smoke, it indicates worn out or broken rings. The rings might be stuck with carbon or corrosion too. If it is steam then it could be a blown head gasket or a crack in the block. If it is black smoke then the carb may be leaking internally.

[Frank Miller]

Your ad says the engine was reuilt but smokes. Was it done a long time agao and has been sitting? Let's approach this logically. If you do put in another engine you need to take this one out. So do that. You expressed interest in selling it. Easier to sel and worth more if it is apary for inspection. Now do that. Remove pan and heads. Maybe take out a couple of pistons. Send us some pics and maybe we can help from there. Whatever route you take you do not have much extra time invested. Sounds like you may have a nice engine with a ring problem.

[Solo_909]

Okay so I found another 51 Merc with a 302/C4 and with the stuff I’d like to do to it already done. With that said someone make me an offer on this one and it’s yours. Save an all original car!

[Solo_909]

So I pulled the Flathead today and here is what was inside. Needs a little more than rings haha.

[Tinker]

That's not scary for a old engine. Flush it, run it. Compression will get better running. Oh course check piston/wall clearance and bearings. Is there a wall ridge? you can see it and feel it with a fingernail.


35$ in plasti-gauge and cleaner, another 100 in gaskets. Might last another 10 yrs as a decent runner.


Or it might be a goner.

[1949f1]

A lot of old engines look like that. Most of the time it’ll wash off if you ever get it good and hot.

[Ggmac]

I'm glad you found one already done . I really doubt want to be a downer but most old engines look like yours . That doesn't mean much , now if I had peanut butter looking oil residue I would agree with you .
I hope you have a good experience and very good friends with real mechanical experience .

[Solo_909]

So what do I use to get rid of all that gunk?

[V12Bill]

If you have put Marvel Mystery Oil in the engine, It could take a while to burn it out. I recently built a 1941 engine and cleaned out the inside with diesel fuel . After my initial start up, it smoked for about 5o miles until the diesel fuel burned out.