Apart from what is written above, we started from the assumption that the engine has been rebuilt with new pieces and according to the usual techniques for this engine that for certain verses had one serious problem.
Everyboby has a MGATWIN CAM must know MGAguru.com and what is written in his...
If a flat plane is cheaper, it weight less, is strongher, is more racing oriented (look at all V8 racing engines Cosworth Ferrari etc, it will never reach 12.000 rpm and so no problem for destructive vibration, wich one is better?
The alloys "ageing" (example Al alloys) are structurally unstable, they are in a state of transition towards a stable state of equilibrium.
Consequently, in the conditions of sliding viscous, it is likely that the diffusion of atoms, increased by temperature and stress, involves the reactivation...
I think you are 10 years back, from many years in cars the installations for NG works exactly like petrol, the difference is only in a pressure reducing valve from 300 bar (from tank) to 10 bar, which feeds electrical injectors (like petrol injectors) usually 4-6 inch before the cylinder head...
This is not a con-rod bolt problem, it is only a typical problem with cast piston broken in pin support area.
With cast piston you cannot have the control of metal uniformity, you don't have control of how it was cast and how it was cooled.
I have 50 years in racing engine, racing, building...
