Cam plate oil hole for timing chain?

I was on one of my hang outs a few days ago and the discussion was about timing chains. I may have seen something like this here, too.

Anywho... the discussion was double row vs. single row timing chains. There were several guys in the business who install single row timing chains on competition engines ie. drag and oval track stuff that is routinely rebuilt. The concensus was single row is fine... but double row sells. The single row seens to require a bit less power to spin it, too.

Looking back almost 60 years I never installed a double row timing chain in any engine until I did my blown Hemi back around 2005. They were not available for most of that time. And I did a bunch of engines of different flavors... SBC, SBF, FE Fords, 351-C Fords, Olds, Pontiac, Buick and Mopar.

Has anyone ever seen a single row chain with iron sprockets fail? I mean in under 7-8,000 rpm applications...

Right now a $29.00 single row chain with cast sprockets seems to be pretty enticing.