[Brian Baker]

And there's the issue of the discharge from the top blower emptying into the bottom blower. The inlet of the bottom blower will always be under boost, and as such will always see "super-heated" air. Won't be very efficient either, as some of this air will be forced toward the center of the rotors (which are coming up at the air)...a spacer that would divert the air towards the outside of the rotors would work better.

With no fuel nozzles between the two blowers to help keep the bottom blower cool, the bottom blower wil prematurely wear.

The top blower will throw the majority of this heated air toward the front of the bottom blower, and the bottom blower will throw the majority of its air to the front of the intake manifold. Definately going to need port nozzles to be able to get any kind of a handle on the tune-up.

In addition to the hat injector, if I were you I'd plumb additional nozzles between the two blowers to help keep the bottom one cool.

So now you've got the hat, some nozzles between the blowers (I'd run at least 4), and 8 port nozzles. What a tuning nightmare.

I'm with Tom, I'd make one of those cases a "dummy"...this way you have the look without the tuning headaches, because there WILL be tuning headaches.

I've seen in person two different cars running that were double boosted...both of them built by Rick Dobbertin. Sometime in 1983 or 1984, I saw Rick's early Nova at a show at the Howard County Fairgrounds. Most of us know it had a BBC with a single roots blower being fed by twin turbo's and a pair of Holley Dominators. It took an enormous amount of effort just to get this thing running. As I recall, when Rick was leaving the show (the car was driven onto the ground, presumably from a trailer parked outside somewhere), it too so long to get it started that they about killed the battery in it and needed a jump start. Once running, it sounded bad a'$$, but he never did anything more than a slow crawl out of the fairgrounds.

Later in 1986 or 1987, I saw his Pontiac J-2000 at Capitol Raceway. Most know this was powered by an aluminum SBC with twin roots blowers (the case that was really one with the 4 rotors laid over against each other at an angle), twin turbo's, and fed by a single Dominator. This car ran like hammered dog $'hit. He lined up against a black '63 split window 'Vette (the one with the monster roots blown BBC that I think was built by Saboury and later sold to someone in Florida, where the car ended up on an episode of Miami Vice). The 'Vette tore out through the first 100' like a raped ape...the J-2000 billowed so much black smoke from the exhaust that it resembled a Kenworth, and it hardly moved.

Having a dual purpose machine can be cool...you just have to ask yourself if it is worth all of the headaches that you will surely have, Bill.