http://store.summitracing.com/partde...5&autoview=sku
I've been running the 2.4 HP CSR for almost 8 years now without any issues at all.
This was on a 505 with 11.5:1 static compression, plus the drag of a 10-71 blower on top. That starter on 12V provides plenty of cranking speed with a 168T flexplate to spin the motor at a speed that the mag will fire.