Russell Engineering can build an MBG engine to your requirements and has also developed many performance parts for the MGB Engine.
MGB Piston Test on the Dyno at 7800RPM
MGB Pistons – $650 AUD
Flat Top 82mm and 82.5mm sizes
Hypereutectic pistons 18-20% silicon.
Light weight at 640 grams complete with rings and gudgeon.
There’s plenty of material to do so. I would put the dish in at no extra cost.
Rocker Support Posts – $240 AUD
Rocker shaft support posts for the ends which will help stop rocker shafts from breaking.
Manifolds – $420 AUD
Crankshaft Machining
Shot peening of the crankshaft radii