I’ll take a cue from Dave and start a new thread with this one.  The basis for this thread originally started in the roller versus link timing chain thread.  Here’s the link to the original thread.

http://forums.y-blocksforever.com/Topic24405.aspx

The oil pump is a major source for the spark scatter phenomenon as pressure pulses from the oil pump are transmitted directly back to the distributor via the intermediate drive shaft.  I’ve either completely eliminated or at least minimized the spark scatter on various engines by either using dry sump oil systems or isolating the distributor from the oil pump itself either through crank trigger ignitions or by relocating the distributor.  Another item that helps to reduce the spark scatter is to use a heavier than stock intermediate oil drive shaft and for the Y, that would be the ARP #154-7906 intermediate oil shaft.

For a racing Y, a crank trigger ignition does the trick and that’s what was used on Randy Gummelt’s Y powered dragster.  But this did require a 10° retard system for starting purposes.  Here’s a picture of a 390 FE Ford engine with a relocated distributor just for the purpose of isolating the distributor from the oil pump without using a dry sump system.  This particular distributor still utilizes a full curve so starting with any kind of high compression is not an issue.

And the link to the larger picture.  390 Ford with relocated distributor 

The style of the oil pump is also a consideration in regards to spark scatter.  Testing with various oil pumps and oil pump pickup designs shows that the gerotor style of oil pumps with an oversized inlet tube has an inherit advantage over some of the other styles in regards to minimizing ‘ignition spark scatter’ in the upper rpm ranges.  Spark scatter is much more pronounced or prevalent when using a spur gear oil pump with minimal oil pickup tube sizing.  I’ll add that any form of cavitation at the oil pump increases the propensity for spark scatter at the distributor.