Stock pump works fine for twins. You can get one for about $25.00.

Carter, Holley etc are some of the big name electric ones you could use, regulator would need to keep the pressure below 5psi or so. Most sidedraft carbs like between 3.5 and 5 psi maybe up to 6 so when selecting your regulator make sure it will operate at low or as low as the pressures you want. But a electric setup will cost at least $250 when you consider the fittings, wiring, lines, pump, regulator etc.

Volume is also as important as PSI so be mindful of that if you're going for a no-name cheap unit. They might have the right pressure but the volume they provide is often insufficient to feed the pair of thirsty bastards.

If you have a surge tank does that mean you will also need a lift pump? is that correct?