For the ultimate in 1275cc overbored engine performance, double heat treated pistons. You can't beat cubic inches for performance, and the A-Series block can be bored far bigger than the factory ever imagined. The standard bore is 70.6mm, the 1380 bore is 73.5mm. This is .120" oversize and should be offset bored as per our half engines
ENG001. Also see the pistons we now use
C-STR311 which has a 3 piece oil ring as preferred by racers.The 73.5mm cast piston set designed by AE Hepolite is great for road/street and mild racing. Rings set for this are
R39390-001.5mm ring and 4mm one piece oil ring or
C-STN97 with 3 piece oil ring which performance engine builders prefer.
- AE Hepolite is now owned by Federal Mogul and trademarked "Nural".
Sold singly,4 per engine required--