The Stovebolt Site Forums The Parking Lot Big Bolts Swapping a 235 for a 261engine out of a 58 bus

In order to make the right decision I wanted to get some input on the chances of me putting a 261 motor in the 48 1 1/2 ton truck I have. The motor is in the truck so I can see how it will run but I wanted to find out a few more things before I got serious on this motor swap. I just don't want to get into the motor and need to rebuild the carb and the fuel pump on another motor.
Distributer, if the shaft is bent like the one I presently have in the 235 babbet pounder, Will any 6 cyl distributer replace it.
Head I have a good head from a 235, will it fit the 261?
Carb, is there a chance I can take the XY carter off my 235 and put it on the 261. I just rebuilt it.
Can I use my present fuel pump off the babbet pounder for the 261?
I just put new plugs in the 235, I may as well switch them over to the 261.
Last but not least the starter and the flywheel from the 235 engine on to the 261 motor.

Thanks for the past input. I hope to get back on the road soon with a little help.

The following is IF the 235 you have is 54 or later, if it's the old High Torque/splash oiling 235 none of the major parts will interchange.

The 261 will bolt in your older truck as follows:
The head will work fine, just compare to the 261 head and drill tiny steam holes between cylinders on the deck surface, use the 261 head gasket as a guide.

You want to compare the front mount plate behind timing gears, and use the original one if you need to for the correct front motor mount.

The only real snag will be the long water pump pulley of the 58, will hit your radiator. As you will have the 261 out of the bus, I'd install an adaptor plate which will allow you to use the older style/original short water pump. I believe the maker of these plates is a bolter on this site, or check eBay for these.

Other than those couple items, this is as close to a direct bolt in as you will every see.

In addition to what JiMerit said, you'll need to use the '48 bell housing. The mounts are different. Also, the starter and flywheel must match. If your system is 6V use the starter and flywheel from the '48. If it's 12V use them from the '58.

The 235 that I have in the 48 Loadmaster ton 1/2 is out of a 1950 chevy car.
I converted the truck over to 12 volt this fall. I use an alternator from a 85 chevy for power.
The starter worked fine on the truck and I was hoping I could put it on the new engine.

The 235 head I have sitting in the garage is off a 1960 engine, I did not know if the valves were typically bigger on the 261?

What are the advantage on using a 261 motor verse the 235? Is there a noticable amount of power difference?
Thanks for the update

For your application in the 1 1/2 ton, you need all the low end torque you can get and thats what the 261 will give you. You want to find a machine shop that knows these old motors and that is becoming more difficult each day as the grey beards are retiring.

There are several issues you want to make sure are addressed with your engine build: cam(stock 261 was a good one and can be reground), rear main/rope seal must be done right, modify the block for modern full flow filter(see tech tips), keep the original 261 rods, use 235 head that casting #ends in 848 for a bit more compression. Plus several other details like aluminum timing gear vs fiber. So you can see that you must do some research to get the best engine job you can. Read everything on this site re. motor and also check inliners.org site for more info. You can also do several things to make life easier like going to 12 volt electrical, modern distributor/electronic, NOS or modern carburetor etc. BTW I kept original bellhousing, flywheel/clutch and starter in my 46, 6 volt starters love 12 volts.

As stated, keep your original bell housing and front motor mount plate, all bolts right on.

All 216/235/261 distributors will fit but I like the later 12 volt units as the points are easier to find and Pertonix makes a kit (#1166) for that one. Also you can modify the later inlines HEI unit to fit your motor.

I have a '45 1 1/2 ton, that I plan to swap out the 216. I have been looking for a 235, am I better off looking for a 261?
By the way, years ago I did a 216-235 swap. I cut the water pulley post shorter, and used a reversed Ford Falcon water pump pulley on the 235 water pump. Will that swap work on the 261?
-Outworld

Outworld, the trouble with the long pulley water pumps in your 45 truck is that when shortened, the fan will hit the balancer and lower rad hose. Plus the fan then will be way low on your radiator, should be higher for best air flow.

The better solution today is to buy this adaptor plate that allows you to run the 216 water pump on your later 235/261 motor. I've seen these adaptor plates on ebay about $40. As hard to find nowdays as the 235s/261s are I wouldn't pass up a good deal on either one. You could waste years hunting down the 261.

The really smart solution would be to find a 53 235 out of a pass car that had powerglide trany (first pressure oiling motor) or any 54 235/261 as these motor came with full pressure and the early style high water pump as did your 216, bolts right in no sweat. Happy hunting.

Yes the 6V starter will work fine if you use the 6V flywheel. The 12V flywheel has finer teeth and won't mesh with a 6V drive gear.

I found a 47 2 Ton GMC with a rebuilt 270 engine. Could this be a simple engine pull from the 2 Ton over to the 1 1/2?

The GMC is a VERY good engine. However, it is a little longer than the Chevy engine so the radiator would have to be moved ahead to make this swap work. I would suggest that you do a search on this site regarding GMC engines and swaps.

Question,are the front plates different on a 1951 216 babbit engine and the 1954 261 engine ? Do i need to use the front plate off of my 216 engine and place it on the 261 engine ? I was getting ready to repair the front plate on the 261, but if i can't use it, i'll wait . I know i have to use the 216 bellhousing, did not know about the front plates being different.

Thanks,Tim

N D,

If the 261 is from 1958, it probably already has the full-flow oil system (1/2" NPT oil line holes on the manifold-side of the block will confirm this).

I have a 1960 261 from a school bus in my '54 (replacing a 235). What people have described above is a good rundown of the conversion. The water pump and pulley were the only things that needed serious consideration.

I converted to 12v and used the 1960 flywheel/clutch&pressure-plates and the 1954 clutch/bell-housing. I cannot remember if I had to swap the front motor-mount plate from the 235 to the 261 and I do know about the 216 front motor mount.

Tim

what are you doin with the bus? i could use some sheet metal. do u have it or kno where it is