340 pistons in a 360?

don-vee said

So, I have heard of a few guys doing this in the old days, using 340 pistons in a 360, I think they called it the Hoover engine. Anyway, I have a nice set of 340 standard-bore pistons laying around (I think, more on that in the second question), and a 360 that's itching for 'em. I was going to have the entire rotating assembly internally balanced anyway. So, besides the .040 overbore, anyone know how I'd go about this, and what issues I might face?
Now, I was just TOLD they were 340 pistons when I bought them at the swap, but how do I check and make sure? What are the differences? Maybe the guy sold me 360 stuff instead, it's happened to me before.

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The Tom Hoover 360 used OEM low compression 340 pistons. The replacement TRW versions (don't have the # handy) may work too. But they had to do a lot of machining on them - milled the tops down, chamfered the outer edge and a cut under the wrist pins to clear the crank. I believe he used 340 +.020 pistons. But this was done before 360 pistons were common. The labor involved today would not be worth it unless you can do it yourself. But you would still end up with OEM cast pistons, not as strong and probably a bigger overbore (+.040") than you need to clean up. I don't recall if or how much the block was decked

The 10.5-1 compression pistons will not work because they have too much compression height and the needed cut would result with a VERY thin top or with holes.