Need advice for lower crankshaft pulley

[cobra940]

Looking for advise on what size of pulley to get for the lower crankshaft on my 03 cobra, I already ordered the metco kit with the 8lb, but have yet to install it.
Quick run down on the cobra;
Cobra is mostly a daily driver
Full Bassani exhaust
JLT cold air
Will be tuned and dynoed when pulley kit is installed And will match the alternator pulley to adjust pulley size.
Everything else is stock.
Basically just would like to know if a 8 is going to be to much with stock upper and stock blower, should I do a 4 or 6?
I know there's tons of threads on this but couldn't find any recent ones.

Thanks in advance(b)

 

[svtshadow]

I would get a 4 lower. I can only imagine how fast that alternator pulley is spinning with a 6 lower. But that can be fixed by a larger alternator pulley not sure size though

 

[cobra940]

If I ran the 8 it requires a 3.70" alternator pulley