Ford ever use the Mercury 255 Flathead in any trucks or Mercury trucks? To stay original looking but add horse power the 255 at 125hp should be a good choice.

 

The only resource I have is a 1953 Mercury Truck Chassis Parts Catalog. It states: The Mercury flathead 255 V8 was used in M500 & M600 trucks in 1953.

AFAIK, the Merc flathead was not used in Ford pickups.

1949/53 Merc passenger car engine specs: Cast Iron Block / 255.4 cid / B&S 3.19 X 4.00 / Compression Ratio: 6.8:-1 / HP: 110 @ 3600 RPM / 3 Main Bearings / Holley 885 FFC 2V.


Ford confusion: The first Mercury Y Block engine, introduced in 1954, has the same cid as the flathead. The same was true for the Ford 239 flathead and Y block. The Ford 239 Y block was a one year only engine. It was replaced by the Mercury Y block in 1955 trucks.

 

Great job numberdummy. You always have the answers

 

What about a 254 Flathead Six? I have a nice 51 254 which was rated 112HP, and 217LB-FT of Torque. The 254 is basically a 226 with a larger bore from the factory, stroke is the same as the 226. Most parts interchange between the two engines. I have also read about people putting a 226 head on the 254 to raise the compression since the combustion chambers are smaller on the 226 head. It should raise compression from 6.8 to approximately 7.5/1 . Bob(rswhitmore@yahoo.com)

 

Ford didn't - but I did. My 48 F1 runs a merc flatty with 52/53 Ford EAB heads for increased compression. I like the combination.

Incidently, you'll find that farmers had a tendency to replace their worn out flatheads in their big trucks with merc engines. My 255 came from a 46 1.5 ton grain truck.

 

I have a 255 in my 1951 Ford F1 pickup. The heads say 8RT, and the previous/original owner says the motor came from a (Wrecked) cab-over Ford truck. It definitely has the 4" stroke.

The extra 12 hp probably won't snap your neck.

If I had to make it go faster, I'd use a transmission that you could shift in less than a minute.

 

A 10% increase in horsepower is a good thing even when you start with very little, by current standards.

 

Well...ordinarily. However, my poor old transmission takes a metric century to grind into the next gear, so any power advantage is relatively useless.

Yeah, I could rebuild it. Or...I could adapt a more modern trans. But I think I will ease into a power train where 10% more is a rude shock.

Too bad. The 255 runs so nice, and the 4-speed is half dead. Throw in the 3.95 rear, and getting to 60 is very intense.

 

That could be something whose time is coming.

 

from what I understood from my flathead supplier the Mercury 255 was avaible in Mercury products such as cars and trucks 1 ton and larger. However Ford advertising was not always true and as either crankshaft will bolt into a 239 block some supposdly 255 motors left the factory as a 239. The way to identify a 255 crankshaft is that a 255 crankshaft will have 3 large round markings on the front lobe of it where as a 239crankshaft will not have these markings.
Since complete rebuilds where more common back in the day you never know what you got in your motor for internals my 1949 M47 pickup (originally a 239 motor) I found out when I tore it apart it has a 255 setup init hence I have a 255 motor. Also I found out my 1947 Mercury motor has the internals of a 1953 239 motor yet the old style block.
As for power gain I know 10 more hp does not sound all heavenly impressive but you must understand that power gain is consistant throughout the ENTIRE power band of the motor and increases routine driveability signfigantly.

I too have heard that 255 motors were only availbe in limited trucks in 1953...1954 in Canada. I dont know how to argue against that point as Im not a literature collector or buff but thats the story I heard, if anyone is looking for a 255 kit I know where they are fairly avaiable. (used crank and pistons)

 

I have a couple of shop manuals that have the 1952 and 1953 power output at 125 hp. and 49-51 output at 110 hp. That is a diff of 15 HP. If that is accurate that is a big jump in HP for a flathead given the same displacment. Is there a different part number for the cams.

 

I believe part of my truck's problem is the combo of low gearing in the rear, and the camshaft that came with the F6 COE the 255 originated in. It will exceed 60, but you wouldn't want to cruise at 60. Having had 239's, I know the 255 gets up to 60 quicker, and especially pulls up big hills more easily. Yeah the F6 had low gears too...but taller tires. I guess I've been jaded by adding 50-100 horse to various fox-bodied Mustangs, and now take amusement from adding 10 at any rpm. I'd still like to cruise comfortably at a slightly higher speed. I have a Lincon 9" with discs that I'm rebuilding. I'll have to add a disc kit to the fronts, and a power-boosted master cylinder, so that'll be after this summer's cruising. A higher gear, a smoother shifting trans and an extra 200 hp (not a flathead) should edge that cruising speed up just the right amount without launching the poor old girl into Warp. PS: I think the 125 HP Merc had a more functional cam with a higher torque and HP rpm than the more truckish 110 horse.

 

Hello all, new to the site with a project just starting up. Hauled home a 1953 Mercury M-250 i now call "The Rig". Last thing left of a Grandpa i never really knew. Has a flathead so far believed to the be the 255. Has the Mercury EAC heads on it for sure and just got it on a stand today. Seized solid so far. Pulled the bell housing off where the mice had made a home. Pretty messy so far but could use any advice or info where to get parts, manuals for the motor, or entire truck, or just any particular markings on anything to make of what i got myself into.

 

There are many sources for Flathead parts, but Speedway (speedwaymotors.com) has enough in their catalog to build an entire motor bottom to top. Their prices are low enough so that they are a handy comparison when you are shopping parts from other sources. Step one may be getting that block checked for bore size (how many times has it been overhauled?) and pressure checked/magnafluxed for cracks. If it passes, you can then proceed to assemble a flatty. They are SMALL in engine size ("4.0") like a Ford Ranger or 3.8 Buick V6, and are only really "hot rods" in the lightest vehicles. You can bump them up to over 300 cubic inches. The catch? Can they breathe like a 300 inch motor? There's the art of it.