Pistons

[Bob Culver]

Tens of thousands of Sevens have each extracted 100,000 miles or so from big ends not belled. it is a racing recommendation ,unnecessary and undesirable for cars driven to reasonable rpm.

The oil rings do not get very hot but I suppose if they butted could scrape too well.

There were a myriad replacement pistons marketed, some dubious. many solid skirt were finished completely circualr without the slight side relief of the originals.