Difference between a 47 engine and a 51 engine?

[The Swede]

Yesterday I was tipped about an engine with a fluiddrive transmission that is for sale.

The person I talked to said that he belived the engine was from a 51 Dodge.

I haven´t talked to the seller in person yet.

I want to check with you guys first.

Is there any differeces between a 47 and a 51 engine?

My thougt is that it would be nice to have a spare engine and transmission if something goes wrong with my current one.

I´m a newbie in the flathead world!!

/Jimmy

[james curl]

If one is a Plymouth then it would be 218 cu in engine and the one from the Dodge will be a 230 cu in engine. If they are both Dodge then they will both be 230 cu in engines and basicly the same. All are short block engines and the basic difference is the stroke is 1/4" longer in the 230 engine. All will fit in the same location.

[The Swede]

Okey sounds good!

I don´t want to buy an engine where no parts fit between the new and my old one.

Thank you for your answer.

I

[Reg Evans]

If both the 47 and 51 engines are Dodge the 47 is rated at 102 h.p. and the 51 is rated at 103h.p. Bore and stroke is the same so it must be a slight difference in compression ratio.

[55 Fargo]

The only other real difference in design between the 47 and 51 engine are this. The 47 engine has an external bypass waterpump design, the 51 engine has an internal waterpump designed block and head, and uses an internal by-pass waterpump.............Fred

[The Swede]

Thank you for your answers!

[builtfercomfort]

I think the most important measurement is the head length. If the Dodge came from Canada it will be a 25" head, if from the US a 23" head. (If from a Chrysler or DeSoto from any year, a 25" head.) And lots of old motors got swapped around.

So check the size out first. A 25" motor can be made to fit in a 23" engine compartment but you need to do some rework - often mount the radiator further forward.

[Normspeed]

I was thinking that, the models made for export may have had some different motor combinations. The engine number from the block above the generator would tell more about it.

[PatS....]

Seems to me that most export models came from Canada. There should be a tag on the firewall saying "Made in Canada"

If both engines are the 25 inch block then they are interchangeable.

[The Swede]

interesting with the head lenght.

My dodge is imported from the US 3 years ago so it´s US made.

I´ll have to ask the the seller if he knows which lenght the engine have.

but what was the point with different lenghts on the engines?

Just curious...

But if the 51 engine is US made with a 23" head, will the head fit on my 47 block or is it different because of the other type of waterpump?

/Jimmy

[48mirage]

If both are of the short block design the '51 head will have a little bump on the front to accomodate the bypass water passage but the later head will fit on the earlier block. I have '54 Plymouth head that I have milled and preparing to mount on my '49 engine. Use the later style head gasket.