pulley?

[willyj]

sbc water pump pulley is approx. 7"-crank pulley is approx.4.75" anyone figure the reduction %?. 20% or 30%? Eng is 409 on gas all steel approx. 500hp 7500 max on rpm. Would you go with these pulleys or 1to1? I will use shroud and good pump.Stewart says 7000 max on their pumps.Im looking into the Edelbrock #8817 but dont see any rpm limit.Oh Stewart also says do not use restrictor.Im leaning toward #8817 pump 1-1 pulleys,shroud,no stat or resrictor.If the 7500 rpm is to much for the pump maybe put restrictor in lower rad. hose. Oh i have 2 single pass rad. dont care to buy double pass. Looking for the correct route the first time guys,THANKS.

[willyj]

ok i will do my own math. What pulley would you run on a 409 sbc on gas? Max. rpm 7500. 1 to 1 or 20% reduction?