Hi Guys
The whole issue of engine swaps have many things driving them. Personally I don't fault anyone for their decision or choice, because it generally means a CMP or other HMV continuing on the road.
I am in the situation where I have HUP with 216 basically original to the truck and fresh rebuilt which is not an inexpensive operation. A Pattern 12 C60L which now has a 235 installed as a fresh rebuild other wise all stock CMP. The third is a Pattern 13 C60S radio box with a 261. The C60S I drove for many years with its stock 216 so I know what driving 10,000 Lbs of truck with 84 Squirrel power in modern traffic is like.
(My average cost for complete engine rebuilds here in the US for the 216-235-261 engines is $2000-$3000)
Putting a more powerful engine may or may not make a CMP comfortable to drive at higher road speed of my three only C60S is happy at speeds above 45 MPH. Even with fully restored vehicles some like it and others don't. I suspect that is just the combination of all those heavy revolving parts and the little imbalances just make some trucks seem very busy and unhappy.
Now back to 235 and 261 engine swap it is possible to install these in CMPs with the stock fan and accessories and the stock transmission. If you don't have a original CMP bellhousing to work with the clutch hole on the right side standard 216 truck bellhousings can be converted to the other side.
The only thing about having the stock 6 blade fan is you need to match all the pulley sizes so that you don't over speed the fan. See
http://canadianmilitarypattern.com/2...ifications.htm for more details. One other complaint from other people who end up driving in front of you. The guys driving Jeeps say they have the uneasy feeling they are going to get sucked in the grill of the CMP because of the fan noise. One guy described it as being like the Follow Me jeep with a fighter with a 10ft prop following him.
One last point about the conversion to other newer engines. As the stock of 216-261 engines is now all now 50+ years old the chances of finding good engines which will not have to be completely rebuilt is shrinking. So pick your engine transmission combination with an eye to what is readily available, physically will fit, but probably most important will end up having a RPM power and torque band not dissimilar to the original engine.
Hope this adds to the conversation and keep those CMPs running down the road.
Cheers