Model 50 pistons

Thanks for the reply Mike,

I have the 'old' piston from my '63 M50, and it has 'HEPLEX' cast into it on the inside along with the number '13329';

I measured it, and the dimensions are:

Diameter ~71 mm;

Compression height (center of the pin hole diameter - to the top of the piston) = 1 - 13/16 inches;

Piston length = 2 - 27/32 inches;  

Pin diameter = 7/8 inches 

I was told that a quality comparable replacement piston is a 'Gandini' and I've located one that matches all these dimensions as it is referenced in the catalog, and the same part number '13329'. 

The reason for my question, was that the ad says it is compatible for only years 1956-58. 

Seems like it would work, but I just would appreciate some reassurance :)

Thanks,

Peter