I've used both
Hi Mike and Bob
I've used both, Bob is correct that at the RPMs the 216, 235 or 261 are turning it probably is not a noticeable or even measurable difference. Equal weight however is more important the entire piston,rings,and rod assembly should be as nearly perfectly matched as possible.
Having said that I taken apart running 216s to discover that they were a total mix and match of parts. One engine in particular had several different types of valves, some of the pistons were over sized some weren't thing must have been assembled out of the scrap pile. But it ran fine. I got it as a spare engine its history is unknown. Right now it is in the Pattern 12 C60L seems to run fine. When the HUP is done the Pat 12 it will get the 235.
Now the 235 came out of a junk yard truck, with serious valve train problems due to an oil line failure of the line to the rocker arms. But it had cast iron pistons which the rebuild shop magnifluxed found them to be OK and reused them along with rods cylinders just needed honing.
The 261 they bored out .060 so it need new pistons and they replaced them with aluminum.
I don't think I would reuse any old cast iron pistons or even NOS with out have them checked for cracks. It's just two messy when they fail.
The only piston I have ever had catastrophically fail was on a J-3000 Jeep with a 350 Buick engine. The number one piston disappeared inside the engine at full throttle plowing snow. After a very load bang there was total silence, opened the hood the wrist pin and half a connecting rod was laying on one frame rail. On the other frame rail was a 4" chunk of the connecting rod. When we did the autopsy of the engine we could not find the piston all we found were lots of little bits of aluminum. Apparent cause piston striking a valve.
Next week the 216 out of the HUP comes apart to decide how much of an overhaul it will need. I suspect that if the pistons need to be replaced I will go with the aluminum as they seem to be easier to get from a known source.
Cheers Phil
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