S1/S2 engine, original

[Lyngeled]

Hello
Can anyone confirm that the S1 and S2 engines was originally the same?

Regards

[jbcollier]

The engines were upgraded as production went along.  The very earliest had a different flywheel IIRC.  They used 1470s (short stroke, siamesed intakes) until supply ran out.  They then used the federalized 1565 (long stroke, separate ports) -- which was already in NA bound vehicles.