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Canadian Poncho Homepage -> Canadian Poncho -> 58-64 Full Size Power Train Tech Forum -> Need some schooling....250 vs 261
Post Info TOPIC: Need some schooling....250 vs 261
MoboMac


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Need some schooling....250 vs 261
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Other than displacement....what are the differences....internally and externally?

What is the easiest way to ID a 261 whilst still in vehicle and covered in grease?

                    Thanks



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4SPEED427


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Definitely not a 250 but I can't tell a 235 from a 261.

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Prefectca


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A 261 and 235 are part of the same engine family. You can tell if its a 261 by two cast in vertical bars above the starter. Sometimes referred to as Captains bars or the number 11. I will try to find a picture. Also be aware of the big truck 261. It will have a full flow oil filter with very large 3/4 inch oil lines. The full flow filter cant be removed, if you plug the ports in the engine you will have no oil flow to lubricate the engine. This should help.

http://www.jimcartertruckparts.com/Articles/261-Engine.php

 



-- Edited by Prefectca on Thursday 15th of July 2021 07:08:02 PM

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MoboMac


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OK....I guess my question would be 235 vs 261...

I will check for the Captains bars...

IIRC...58-61 Canadian Pontiacs and GMC trucks came standard with 261's.

Is that correct?

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58 poncho fan


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Cars were from 1955 to 1962.  Not sure about trucks.  Bob previous owner of a 1958 Parisienne with a 261.

 



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MoboMac


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Ok....founds the Captains Table on the 59 Stratochief.......but not...on the GMC.....but Transmission on the GMC looks to have been changed....so maybe engine too?

The 235 has an oil filter can...on the left side.......Were these a good thing?

I heard on the earlier engines they restricted oil flow..

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73SC


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MoboMac wrote:

Other than displacement....what are the differences....internally and externally?

What is the easiest way to ID a 261 whilst still in vehicle and covered in grease?

                    Thanks

I created this thread in the Library in 2009.

The 261 Story

Its pretty good.



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MoboMac


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73SC wrote:

 

I created this thread in the Library in 2009.

The 261 Story

Its pretty good.

 Great info/read.....thanks for posting....

Looks like I have one 235   and one 261.....

I guess the # stamped on the machined pad on firewall side of distributor....should match engine # on S/N plate...if engine is original?



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Taylor55


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Yes and most Canadian 261 engines start the serial with a W before the numbers. I have the original 261 in my 55 with almost 104,000 miles. I also have 2 other 1955 261 engines.
Al

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