Inliners International Forums General Discussion Engines 261 Chevy

I know a guy who has some '51-'62 Chevy truck engines. He thinks they are mostly 235s, but there may a couple of 261s, too.

How can I tell the difference between 235s and 261s?
It's been over 40 years since I've worked on a 235, or 261....memory's fuzzy.

I'm sure there's serial numbers that will indicate which engine it is...anyone have any guidance to suggest?

Thanx in advance

Dennis,

Look at the link to "The Forgotten 261" in the Tech Tips to the left. It shows where to look for the casting numbers and the Captain's bars.

The Captain's bars are not an absolute indicator, as I have a 1954 261 that does not have the bars and the casting number indicates that it is a 235. However, it is is most certainly a 261, but the head would need to be removed to tell for sure. This engine was purchased as a new replacement engine, and Chevrolet must have used the wrong external patterns when it was cast.

However, I have not heard of a "false positive" - numbers that say 261 but the engine is not.

Also, if an engine has a full-flow filter with 1/2" NPT fittings and hoses it is most certainly a late 59-62 261. Hope that i did not confuse you!

Dear Dennis;

Mr. Hoyt, "pretty much" sums it all up.

Start by looking at the ones with the 'later' water pump opening (single 3" hole) & go from there.

Long ago; we used to take a Qt. beer bottle with us. It would fit the 261 but not the 235. It provided an excuse to buy the beer too.

Happy trails.