i ordered a set of under drive pullies from FPS when i ordered my tranny and they told me the pullies were on backorder and we discussed the design of them a little. 
from their website. well i’m unsure about running a solid crank pulley. yesterday i recieved the crank and alt pulley. any thoughts?
is it still lighter???..it does look odd…but MEH…as long as its not unbalanced
Call them and ask them why they designed it that way.
I’m sure it was cheaper to build it without “spokes”.
the crank pulley is 25% smaller and the alt is 25% bigger so there is a 25% reduction on everything and 50% on the alt. now maybe i won’ smoke 1 alt a year. the new pulley is at least 15lbs lighterthatn teh stock one.
the SHO uses a harmonic dampner and is internaly ballanced. my concern is about me removing the dampner. the engine already has 216K and it has another 200K to go i don’t want to kill it becasue of a silly pulley.
I would run the stock balancer. Some of the SHO vendors have stoped selling the 4 pully kit and offer only the other 3 minus the crank pully. Its not worth it to me. Go with the stock damper and be safe.
cost is the answer. It was cheaper for them to make that and not spend anymore money machining
the way they sit now, they were lathed / cnc lathed into that shape, adding the spoked would require a cnc mill also, adding to the cost of producing the pullies
lots of people are using them, i think i’ll give it a shot. it wil make running my “down pipe” (it doesn’t really go down at all lol) easier
if its 15lbs lighter then forget it your good(performance) but if it was all the same price i would of try to get em with spokes that can only make em even lighter i would think.
they just look weird thats all
^^^^ to late - pully is in
he has a spare motor anyways … if shit blows up its swappy time