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ENGINE IDENTITY


shull

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Just bought a 25" engine that does not have any stamped numbers on raised pad on left side of block.  Only stamped  number is on the Spitfire head; which is S-267.  Anyone  got an idea about year and displacement ?  Thanks.

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IMO, without the stamped serial numbers on the pad on the block, the only sure way to tell the displacement of the 25" engines is to measure the stroke. The bore is the same on the three most common size engines (237, 251, 265 cu. in.) but the stroke is different and the rod length of each is different. Remove the pipe plug located on the head between cylinders # 5 and 6, and using a long thin wooden stick in the hole, rotate the engine and measure how much the stick moves from top dead center to bottom dead center. The stick will be resting on the piston top and move up and down as you turn the crank and thus reveal the stroke of the engine. I say wood stick.......just in case you use a short one and in disappears into the cylinder at BDC. :eek: You don't want a piece of metal stuck in there.

I've bought a couple 25" engines that turned out to be smaller than I thought at time of purchase.

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That head number was used on the 251 and 265 CI motors. Can’t pinpoint the year isn’t was cast. The -1 Number shows that it was the 1st series cast.  Look around the left rear bottom of the block above the oil pan. The block casting numbers be there. You might get lucky and the casting date of the block will be to the front of those numbers around the distributor hole area. I would just do what BobK recommended. That will tell you the stroke and you can go from there.  Good luck.

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41 minutes ago, shull said:

Can you tell me the brand or year of production from this casting #.. Thanks

Dozerman beat me to it.........so I'll tell a story.

Once upon a time, an "unknown" :D person was looking to find a 265 Mopar flathead. Off he went to the local machine shop and poured over a book listing all the casting numbers of 25" Mopar flatheads and he reasoned that with the list of numbers, he would be able to identify the 265 engines from the 237 and 251 and all would be good :cool:.  But after writing down lots of numbers it became apparent that this was a poor plan :(. For example.....# xxx-4356 block was used on the 1951 265 and also on the 1949 251 and 1947 237 and..,....on and on....

 

Remember the old saying......size matters.....use the stick and you'll know how big it is.

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Howdy Shull  -   The fact that there is no stamped number of the block likely means at some point in time the block was cracked or could not be bored out any further and someone bought a replacement block.   The casting number on the block and the head actually do not  really provide you the information one might hope it does.   For the year of the block,  on the oil filter side of the block,  right close to the oil pan and close to the oil filler there will be the date of casting.   It was used for internal purposes as  blocks became generational items that often were used over several years and several engine sizes.   The last generational change for the 25 1/2"   Canadian engine was october 1951.At that point the block was carved internally to

allow for the 4 3/4" stroke motor for the 265 ci motor, however that block was also used for the 238 and 250 ci motors.    Same block same bore for those 3 just different stroke.

After 1955 the year was actually dropped as there was no further block generation.  So if your block has a month and day  but no year code is was cast after Jan 1955.

 

So your back to the strokes  using the method BobK outlined will tell you if it happened to be a 238 (4 1/4" stroke)    250 ( 4 1/2" stroke) and 265 ( 4 3/4" stroke)  although you could also have a 228 ci motor or several other cubic inches with a spitfire head  on it.  As well while the 238, 250 and 265 are 3 7/16"   bore stock you would have to remove the head to  know for

sure the cubic inch.

 

I would however do as BobK suggested as a start. Pull the brass plug and measure the stroke. That really narrows things down quickly.

 

Tim

20171121_123922.jpg

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