ID Dodge flathead 6

You guys are pretty good at ID'ing stuff so I'm going to try another one. There's a couple things working against me in terms of finding the exact size without opening it up.... a) it's probably Canadian built, and it came out of a 54 Dodge 3/4 ton pickup. It's a "T" block (truck) so it' likely the original motor. The block number is T-339 1195C. From what I can find on the web, it's most likely a 228 or a 251. Can anyone pinpoint which one from the numbers, or will I have to pull the little plug over #6. I believe the 228 has a 4 1/4" stroke while the 251 has a 4 1/2" stroke. From what I can find they both have a 3.4375" bore (edit- that's incorrect, see Rusty's reply below). The casting number on the head is 253, with the numbers 1327337 under it if that helps. It's a 25" block, but Canadian trucks were also known to get smaller sizes with the longer block. I'm hoping that it will propel a speedster for me some day. I heard it run when it was still in the truck and it purred like a kitten.

T339 is a 1954 - 56 Canadian made Dodge truck engine, 228 or 251 cu in. Can't pin it down any closer than that.

The 228 has a 3 3/8 bore X 4 1/4 stroke. The 251 has a 3 7/16 bore X 4 1/2 stroke. Both use the same engine block and the 3 3/8 bore block can be bored to 3 7/16 or larger.

There was also an engine with the 3 7/16 bore X 4 1/4 stroke, this was a 237 cu in used mainly in DeSoto cars. Not used in the 54 - 56 truck line.

Either way it would make a great engine for a light weight vintage style speedster.

I have some spare engines and parts including parts to build a 265 cu in, 3 7/16X 4 3/4. The largest version of this engine made.

I was thinking that those numbers I posted didn't look right... tells you some of the sources out there are pretty sketchy. I was looking for one of those 265's but I have yet to find one around here. I'm surprised this one is a bigger motor actually because most of what I've seen were the 218's. I'm thinking about switching this one to 12v neg ground so I'm not sure how many problems I'm going to run into for starter/ring gear clearance. This one has the truck engaging pedal so I'll probably have to look for a late 50's one from a car. Right now it seems to run pretty good so I'm not planning to open it up until I have to, but from what you say, does this mean I could bore it to 3 7/16 and just use the 251 pistons and standard rings? I guess the other question is differences in rods. If I eventually spring for a high compression head that would be getting up to respectable power for a speedster. I've got the truck 4 speed so I should be able to push the rear gearing a little higher for highway cruising.

Yes, you could bore to 3 7/16 and use stock DeSoto/ Chrysler size pistons. Vintage Power Wagons has NOS pistons for $75 a set of 6. They have lots of other parts, the Power Wagon used the same engines up to 1968 (military version).

I actually have an industrial engine with the large 3 7/16 bore and 4 1/16 stroke crankshaft usually seen in the 218. It displaces 225 cu in and came that way from the factory in the US. So, you can mix and match the different pistons and crankshafts as long as you use the rods that go with the crank, they made different length rods to go with different stroke cranks.

If you could find a 1956 - 59 Dodge or Plymouth car in a junkyard they had the 12V equipment, the 12V starter has a different pinion gear and different flywheel (more gear teeth). The 6V starter will work on 12V especially if you replace the field coils with ones from a 12V starter. Also the 56 up head has more compression, the best head is 58 up. Your head will automatically give higher compression on a larger displacement, and it can be shaved or planed .060 for more compression.

Dodge trucks used the flathead up to 1962 in the large 1 1/2 ton and up. The 265 was used in Chrysler Windsor 1951 - 54 and Canadian made DeSotos 53 - 54. They made many industrial engines in the 265 and 251 size, that rusty old Massey combine may have one.

I would suggest you do nothing to the engine in the way of overhaul or hop up until you get it in the car and running.

One exception, while it is out, it would be easy to remove the pan, clean out sludge, and clean the oil pump screen. While you are at it clean out the valve chamber. Clean and paint the engine and let it go at that. You say it runs well, don't mess with it. If you drive it for a year and work the bugs out of your special, then you can make up your mind if you want to hop up the engine, but do yourself a favor and don't overmatch yourself right off the bat.

Thanks Rusty...that's good info to have. The plan for now is to get it installed and moving like you suggested. I've heard of guys running 6 volt starters on 12 v before, but would switching it to negative ground be an issue? I remember when the rebuilt industrial 251's used to be for sale in the Sears catalogue. Not so handy now.

would you be able to post a couple of close up pics of the front engine mount setup? I have to make up a frame to mount the engine in my Speedster project. I have heard nothing but good reviews of these engines and was told by the owner of a Chrysler 72 powered by one of the industrial versions that they have the torque to lift the front wheels off the ground if you dump the clutch!

LOL... I think popping wheelies is a little ambitious with less than 200 HP but I did drive a little 218 for several months with no first gear. Launching in 2nd was no problem, until I fried the clutch. These engines have lots of torque, but not really high horsepower and I think people often confuse the two. Great little cruising motors but not big on maximum performance. That being said that old 52 Plymouth was a heavy car, and I blew the doors off a brand new early 70's Pinto so it's driveability was actually quite good for the size of the motor. I"ll post some pics of that front mount in your speedster post. It's pretty simple and was part of Chrysler's "floating power" campaign. Basically by mounting high on the engine they were able to eliminate a lot of the wobble and vibration associated with the 6 cyl. engines. Look around for old Massey or John Deere combines from the 50's, grain trucks or dead 4 door cars and you should be able to find one you could adapt fairly easy.