How much underdrive are the underdrive pullies? I heard from a good source that the PS pump will start to eat itself if you spin the motor above 5600 too much, and will be putting a 5.3L with truck accessories onto my 77 Impala. I am going with an LS6 cam, and want to spin to 6500.

 

the cost is around 250 for the underdrive pulley, I run mine to 6800 for the last 1.5 years.

 

i have the LS6 cam right now and i only spin to 6200. do you really think that there is power up to 6500? are you planning on getting a stall and what is the PS pump

 

Stock truck pump. I have not picked a cam, but am building the bottom end for 7k. LS2's cut fuel at 6600, just want to make sure my accessories don't get over spun. I have killed PS pumps and alternators from over spinning them, I figure I can eliminate my issues if the underdrive slow the bits down. Looks like the pulley I am looking for slows the drive down 25%, so that will keep the PS pump alive.

 

Are You Looking At The Asp Crank Pully? If So, I Believe They Are 20% Underdrive

 

for track use i totally bypass the powersteering and alt. pulley. good for 10hp/10tq.

 

I haven't ran the pulley on these trucks but the overall consensus is what cajun boy said... 10hp... and anywhere from .04-.10 in the 1/4

sound about right guys?