Rebuild Dorie: Engine: Pistons

[Patrick Buchfink]

Here is a top view on the cylinders:

As promissed by the vendor, the motor is already overhauled. The cylinders look properly grinded and the cylinders fit perfectly. The vendor told me that the 1300 pistons are used to higher the compression ratio. From the imprint on the pistons I reckon that the bore is also enlarged:

The inprint says:

81.707
1.3HC
S6

So the bore is enlarged from 80.978 mm to 81.707 mm. Unfortunately, I forgot measuring the stroke. Since there is no crankshaft contained in the spare parts I assume for now that the stroke is unchanged. That would give 1628cc instead of 1599 cc.

Does anyone recognize these pistons or does anyone know where I can find further information on these pistons? I could only find little information online stating JCC pistons with a 81.707 bore but saying Ford 1600. Can someone help?