The Stovebolt Site Forums The Shop Area Engine Shop 216 to 261, radiator capacity?

I found a 261 engine which I thought would be a good upgrade to my 38 1.5 ton. However, I am now wondering if I will need to upgrade the radiator as well. After all, the 261 has 50% more horsepower which means the capacity to generate a lot more heat.
Can anyone who has done this swap chime in on whether they had overheating problems with the stock radiator? I’m in southern Arizona by the way. It does get warm here from time to time.

Great question, and one thing I might add if you have not addressed it already, is the clearance between the fan to the radiator. I'm not sure how a 1938 truck is set up, but for example on my 261 that I am putting in my 1953 1/2 ton, I had to use a special adaptor plate on the front of the engine that moves the location of the water pump about 2" to allow it to be centered in the middle of the radiator, and also had to use a short-shaft water pump from a 216 engine. Just something to think about.

I have installed a number of 261s using the stock radiator.
One is now in Arizona. He even pulls a teardrop trailer with no heating problems.

Thanks for the input. It sounds like I’ll be ok starting out with the stock radiator and seeing what happens. I had read about the water pump issue and it sounds like the adaptor is the best way to address it.
I was debating about changing out the 216, but this will never be an original show truck. I figure I might as well make it a little more roadable with the 261. My next debate is whether to swap out the torque tube rear end to get better gearing to go along with the 261.

This being a 1 1/2 ton you may want to ask that last question the guys in the Big Bolt Forum....or the Driveline forum. Depending on what you put in place of the one you take out may open a can of worms as what mates to what.... I have not experience with what you are contemplating but I have had some issues with smaller vehicles.

....I have a 261 engine in my 50 coupe, with the water pump adapter, and have let it idle for a long time just sitting in the shop. No problems so far. Not ready for the road yet.

I picked a '49 "Desert Cooler" radiator out of big truck at a junk yard and put it in my '52 3100. There was interference with the top bar of the radiator support as this radiator is taller than stock.
I cut a notch to accommodate for this.
It is thicker than the stock radiator, but that extra thickness is toward the front of the vehicle and fits inside of the radiator support. The rear of this radiator, once installed, is located just the same as stock radiator. The bolt holes are in the correct position for a 3100.
Carl

Was this done because of heating issues, or just for insurance?

Dave,
Necessity. My original sprung a leak. I still have that Desert cooler in a storage shed. It served me well. Now all I need is another truck to put it in.
Carl