Big thanks to Rob for getting two OEM pullies to me with less than a days notice!
Serdi condemned my others and suggested that they were not suitible for the new engines that they are machining and balancing. (Mainly due to the high RPM limit)
A word of caution to other OEM pully users (EG 95 % of the club) your pulley may look in good condition but when put under load it could be a natts ■■■■ away from exploding! (Like two of mine were)
Get them checked…
Rob I owe you a beer!
Mark 
Just a thought, but if the block is being built and balanced by Serdi would it be possible for you to use an aluminium pulley and get them to balance with that on it? I’m not sure if that’s how things work. :oops:
Glad i could help you Mark…
Cheers Rob
You could but the alloy pulley still wouldn’t be dampened; this would be fine if you like changing your bearings ever few thousand miles. Plus the more weight you can have on the end of the crank (i.e. the pulley) the better, if your looking to make big power.
Mark
EDIT:
That is what I just posted too :lol:
Basicaly the crank will flex at higher power levels so the more wieght you have to try and keep the rotating mass more even the better, plus what Mr B just said.
There will be far less flex on these cranks than on an OEM 6G72 crank as the cranks are a hell of a lot stonger but why take the risk…
Mark