More specific: A roots type (or screw type) has two interlocking screws that force the air charge into the engine and is mounted directly on top of the engine. A centrifugal type is mounted off to the side (like your alternator) and has a fan assembly inside that blows the air charge through some air ducting into the engine. Both types are driven by a belt off the crank.

Roots type:
Attachment 300720

Centrifugal type:
Attachment 300719

Whipple's are a bit different than a roots type. Here is some good info.
http://www.whipplesuperchargers.com/....asp?PageID=79

Nice....I guess now is where I ask how much should I expect to pay per motor to get a Whipple charger screaming?:D

About $8500 a motor + or - depending on your fuel system.....but it is hands down the best system and it will fit inside your hatch without mods most likely.

500's should already have headers or at least Gil exhaust?????

BTW, did you get a new boat????????

If you go with blowers, you better make sure the person who sets them up knows his chit or all you're gonna have is some 20k worth of anchors. Also, you better have a boat with hyd sterring and some good drives to handle the power.

There is a used Whipple on E-bay right now off of an hp500 carb engine. Just FYI.

I can tell you from experience (automobile:D) that the Whipple makes more boost at a lower RPM than a B&M!

What brand of aftermarket springs is a good bet to put on these motors? Also what is the size of tthe springs?

To answer your question Griff...no I din't get a new one yet...I am looking at a few different ones right now and I am trying to see what is the best one for the money.

I'll keep you posted....:ernaehrung004:

Get the best boat then worry about going faster after you get used to it. You better check into insurance in LA. It could be difficult to get from what I have read.