I have seen both set ups on set ups on carbureted and both make great power. What is the real advantage from a roots style vs centrifugal on the street besides heat and visability. Besides the Pro Charger is anyone really making any good centrifugal super charges for carbureted big block chevys?  

I think about the only advantage to a roots blower is nostalgia...

The pressure on the front of the crank, the parasitic losses, and extreme heat generated all make it secondhand to a centrifugal charger in terms of efficiency. The four digit horsepower numbers come easier with a centrifugal charger.

Check Vortech and Paxton for a couple more ideas.  

Gotta diagree. Centrifugal blowers generate heat just like a roots blower, no advantage between the two there. Parasitic losses are the same for both blowers because they're both driven off the crankshaft.

The disadvantage of a centrifugal blower is it takes up more space on the front of the engine, so you gotta make sure you have plenty of room for the install. The disadvanatge with a roots-type blower is hood clearance, which can be a problem with some cars.

If the centrifugal blowers are so much better than roots blowers, than why do the GT500 and new ZR1 both have roots blowers? The ZR1 uses the new TVS rotors from Eaton which generate less heat and more power at loewr boost than standard roots blowers, and even some screw type blowers.

What kind of car is this going in?  

1970 Pro Street nova  

if you've seen the dyno numbers than you clearly know.
roots start boost earlier.= more torque.
centrifugals are more efficient in the upper rpm's = more horse power.
twin screw = alot more power than roots, all around,+ alittle less power on top than centrifugal.

i'd get a centrifugal for better gas milage.and top end charge.
twin screw = probably offers the best of both if you don't care about gas milage.
vortec makes a good carb blower kit too. i'd get an after/inter cooler with either. it's added detonaition secutrity.