My long block is near completion and I am trying to decide which supercharger to go with. The 12-71 I have from a friend is too big for my street application (It is for sale if anyone is interested). Here are the particulars so far:

496 CI BBC - 4 bolt main with ARP studs
Eagle forged crank and H-beam rods (ARP bolts)
JE Blower pistons, 8.5:1 CR (Polydyne coated)
Clevite 77 bearings (Polydyne coated)
242/256 duration at 0.050 with .646/.646 lift at 114 LSA hydraulic roller
Pro Topline Iron rectangular port heads, ARP studs, 2.25 intake and 1.88 exhaust (Ferrea), ported and polished
3700 lb 1967 Chevelle
Backhalved with Ladder bar suspension, 33 X 21.5 X 15 MT on 15 X 15 Convo Pros
Ford 9" with Strange axles, 4.30 Detroit Locker
Turbo 400 with 3000 stall converter
12 point cage
Power steering and brakes
Body and interior not yet complete (will be painted silver with a black interior)

This will mainly be a street cruiser with 2-3 trips to the track each year (test and tune). I anticipate driving less than 600 miles each month. With the backhalfed Pro street set up, appearance is important. My goal is to make about 800 rwhp and similar rwtq. I anticipate not needing to go crazy on the boost (6-8 pounds).

I have a blower from a friend, a 12-71 Mooneyham that is too large for this street car. But that leaves me with which blower to run, an 8-71 or a centrifugal (carb blow through). I ran a Vortech Y-trim on my 97 SS Camaro and it was wicked. It was fairly reliable and made plenty of power but cost a bit to maintain (Belts, etc,). It also lacked was visual appeal in terms of the blower. It was tight and cramped under the hood. I know that the area under the Chevelle hood is greater, but I am not sure how the plumbing will work and what the temprament would be on a big block. Just like everyone else, I want it all, reliable power and visual appeal.

I am interested in hearing thoughts and opinions on this as I try to decide which way to "finish" my project. I guess the main points for me are:

1. Reliability
2. Visual and auditory appeal
3. Power
4. Cost
5. Maintenance cost and frequency

Thanks in advance for the comments.

wow!! THAT'S GONNA BE ONE BAD CHEVELLE! :eek: I would go with a blow through ATI procharger. They are about the same price and they whine just as much as roots, plus they come with a "street" air-air intercooler. This set up would be great and you could even get away with running around 12-15lbs of boost w/ the intercooler no problem. Wish it was my set up!!

Your motor is very similar to mine, but your cam is smaller. I'm running Comp's bigger mechanical (more duration but less lift, also 114lsa).

In my opinion, you have a choice - make more boost, or make it look cooler. The centrifugal will give you a lot more usable boost than the 8-71 will, but there's no substitute for the coolness factor on the 8-71.

I'm guessing you could comfortably run 8-10psi of boost with the 8-71, which is going to overpower the rear tires very easily on the street. With the centrifugal you could easily make a lot more boost, but it's a little different as it will follow the RPMs a little more, whereas with the 8-71 it's starting at idle, or just off idle.

My car is backhalved too, and while it stays straight, the amount of HP and torque that my motor makes is on the edge of what the chassis can deal with. With a good 10pt cage, it helps, but there is chassis misalignment as well as some chassis flex (rolling) under hard acceleration (when the tires stick). The car leaves hard when the tires are warm and the road is good, and this is when the chassis flex occurs. It's mildly disconcerting, I'm thinking I should do something about it. :D

For cruising and an occasional trip to the strip, I'd go an 8-71, it's so much more fun IMHO. But, if you're looking to make serious boost, a centrifugal will make you more boost, cooler. You're probably going to want to upgrade the chassis some though to be able to use that 15-20psi of boost.

I guess what's cool is all in the eye of the beholder. I think there's nothing as cool as a WICKEDLY fast car with a flat hood or a mild cowl induction hood. The Procharger will work under a 4" cowl.
Having said that, I have a friend who has an 8-71 on a small block in a 66 Chevy II. It has 2 Holleys, iron heads, and runs 10.50's at 133-134. He drives it everywhere but those carbs suck water when it rains. It only has 9x28 silcks, too.

I guess the point is it's going to be a bullet either way but when you have a blower sticking out of the hood you'd better BE fast. JMHO!

Randy