Speedmaster Rods, can i trust them?

Why the heavy piston ?
He bought them when he first built the motor in the 90s and his plan is to reuse them i think, but this was when there wasnt a hole lot of other good options, then the 340 had a cast crank, 508 cam, .202 j head and a M1 intake, it ran 12s then, also it had a factory frame and floor stil

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