OK, back to the top. So my bud bought a boat with a 572 basket case motor that used to be turbo. All the internals look good and it was set up for boost. We were thinking 1071 or 1271 but found a deal on a 1471....opinions?

How much power is he looking to make?

well, with that much displacement, that size blower, intercooler, dart aluminum heads...I would think a 1000 would not be out of the question.

Generally speaking, going from a 10-71, to a 14-71, will allow a 10% reduction in blower speed, to net the same boost. In other words, lets say with a 572ci, and a 10-71, you need to be 10% overdriven, to make 7lbs of boost. Going to a 14-71, will allow you to, run say 1:1 pulley ratio and still make 7lbs of boost. At full throttle, you'll have about a 600RPM difference in blower speed, which isnt huge.

1000HP shouldnt be an issue, and either blower will support it. I'd think the choice boils down to the specifics of the actual blower, and price.

that same engine will make around 1200 hp with a 8.3L whipple.

$$$$$$$=whipple

You missed a couple $$ signs lol

yes this is an expensive game we play!

What about idle quality with such a big blower..

can do that w/ a maxed out rpm'd 4L,Have a few of them out there.And on the west coast they'll make even more,,just ask SB.:D