Finally got the aluminum 15% under-drive pulleys in today.

They have a hard-black anodize on the belt surface like the other pulleys in the set.

All the pulleys used together still work great with the stock length belt.

I compared the voltage output of the alternator with the stock steel pulley to the output with the alum under-drive pulley. At idle with the high beams and heater blower on full, they both read the same; additionally, there is no change in output as the RPMs are brought up.

Cheers,

Chris