Couple of options I would look at is Driveline 7mm or 10mm crank with their top end LP timing if your not wide open all the time
421 serval ported
both set ups 35mm carbs
CPI or Shearer pipes for the DL cylinders, add Snipers for the serval
Driveline, Herr Jugs, or Powerline Performance to do the work, they can get it done quicker
JMO