Cross drilling pressure drop ?

[SJ Lambert]

So, I could squeeze in at the front, centre or even rear of the main oil gallery (engine doesn't mount off the traditional mounting point - oil filter head does - could even juggle that a bit if necessary....)..........

[rgh0]

If you have an alloy block with no cross drilling then you certainly need a tapping on the exhaust side gallery.

If you have a big bore, long stroke and more flexible alloy 2 litre block BDA running at 10000 rpm then getting enough oil to a rear main that is being hammered by big weights at high speed and flexed out of alignment with vibration may be an issue.

For a iron block 1600 twink it just does not appear to be necessary at least in my experience. I am sure it can be done but I am not sure if it needs to be done

cheers
Rohan