The cool part about electrical fans is they can be turned of when not needed, where mechanical cannot. Even when a clutch fan is slipping, they take power. In terms of friction, in a small block I dont believe there is a huge savings. In a big block, certainly is. It's a shorter arm so more force is required, and the end of the pushrod on the cam is a small surface area so again, more force thru the smaller area. I dont think we're talking 10s here, probably more on the order of 5 or less. But it's there. The larger the pump, the more power it saps. On teh up side, most mechanicals do not need regulators and look less menacing. I use the Carter HV pump that looks stock for most of my street stuff. Or a stock one. I have had no starvation issues, even using a stock pump with 150hp plate system ona 340 and 175 plate on a 383. But were stock aftermarket replacement pumps and 5/16" line with no returns. I like the service bonuses teh electrics give, but they have a place, and mild builds are not them IMO.