235-261 Conversion Information

[Phil Waterman]

Hi All

Through the years the topic and issues of engine changes for Chevrolet CMPs has come up. Having just completed reinstalling a 261 engine in my C60S I've started updating my web site to include more information. I've added two new pages

The first includes many of the engine pages out of the 1960 Chevrolet Truck manual and will be of interest for those who want to compare the difference between the 235 and the 261.
http://www.canadianmilitarypattern.c...e%20Manual.htm

The second is more observations and information on the process
http://www.canadianmilitarypattern.c...ifications.htm

I'm working on another about the tricks of the conversion.

Thought I would do this as a link as the pages use up a fair amount of space.

[Bob Carriere]

Phil.... CMPers around the world owe you big time...... the information you have on your site is fantastic.

????? What year of the GM manual for the 261 engine did you reproduce...?

Also..... when we installed the water pump and throttle on my 261 we found that the cast elbow.... the one holding the thermostats at the front of the engine can all be slightly different. On a original 216 CMP engine the bottom section of the elbow is cast with a flat surface on the front part.... almost at 45 degrees.... the extra space from the flat area gives just enough additional room for the throttle linkage rod that bolts on the water neck bolts...


Have you noticed that difference... it makes sense to salvage the part off an old 216 for that purpose...... mine came off a GMC ..circa 40-50... in a 248 cu size...

THere is also another different cast elbow....presumably for civilian use... that has a raised web....re-enforcement ? .... at the bottom and the bolt head are half encased by additional casting metal which requires a lot of grinding flat to be used on a CMP..... the front throttle backet will n ot fit the civvy unit without massive regrind...

Can try to find some pictures if necessary..... can't remember if the elbow had a different casting number with the flat......

Also...... using the special 216 throttle bolt for the bellcrank.... the one under the carburator that is connected to the water jacket and leaks antifreeze in your face when you replace it...... we are probably the only two dummies willing to admit we did that...... changing the bolt stud makes using the 216 bellcrank a lot easier......

...and I anticipate further problems with my 261..... if you look at the stock vacuum line coming off the side of the intake manifold. one fo the GM manual in the PCV section has a picture....a huge brass thingnee sticking out..... well..... I assume the tight space of the engine cover for my cab 11 will necessitate that I relocate that connection elsewhere in the intake area..... ????

Any advice from your cab 12...?

Will know more later this Spring...

Bob

Here is the offending stick 261 vacuum connection block which will interfere with the engine cover side panel.....