hey men ,get that stuff out ! who cares for AC with 2 turbos on board ? you willl reach your destination LONG before it's getting to warm in the car ! There is even a more complex side : WHY in gods name do whe want to be that fast ( so less time ) in the place whe loved the most ? 

Just as reference, the longer compressor is the A-6.  The short stubby one is the R-4. 

And now a word of caution.  The A-6 has it's own oil reserve.  The R-4 does not.  In all A/C systems the oil circulates with the freon.  But the R-4 had a problem in some cars when it was mounted up high in the engine compartment.  At start up of the compressor, it was starved for oil, and as such has a short life do to start up wear.  When mounted low the oil ran down hill in the lines and this was not a problem.  A new design of line was created for some of these cars.  It has a reserve chamber in the line.  Oil collects here and when the compressor is started, it get a large gulp of oil and prevents the problem.

So if you switch to the R-4, be sure to up date the line style.  Those compressors sit up fairly high in or cars.

Do you really need Ac up there in ND?

That black box is a cover for the heater equipment.I just saw a `69 with it removed on Friday. gives lots of extra room.

well, then, it seems like the only thing that's really going to be in my way is the AC compressor...I wonder, if I swap to the R-4...if I can find a way to custom mount it as well...over toward the fender more.

Just keep one thing in mind.  The long belt run to the pullies have a tendency to jump off at high rpm.  Even some of our alternators or original A/C compressors had that problem.  Mostly on big block cars.

Some of our cars had a special bracket that the belt would actually slap a bit at high rpm, and it prevented it from popping off.  Just food for thought.  An additional pulley could also be used.  This would effectively shorten the belt span and stop the problem.

You may also be able to mount the compressor down low.  Just a guess I haven't taken a good look with that in mind.

kstyer38805.7422685185

I would check out Turbomustangs.comFor some research. There is a ton of information about turbo's on there And they also have a devoted GM section on their forum. You can look over all the different set ups on there for inspiration. The banks kit is really nice and all but rediculously expensive. especially for only a 650hp goal. If you are patient, You can see how my set up will turn out on my car. I am in the middle of doing a home built single turbo setup at this very moment. I will be taking alot of photos and documenting my progress. I hope to get it up and running by early summer. It is going to be a very simple set up using a single Gt45 turbo, 327 vette 2.5 inch rams horn manifolds and a blow thru holley 650 double pumper and a Water/methanol injection system activated by a hobbs switch. I will be starting out with 6 psi of boost and will progress to 10 psi as I get the tuning right. the fuel pump will be a carter race mechanical pump with the vents boost referenced so that fuel pressure raises up with boost pressure on a 1:1 rate. This will keep fuel from being forced backwards once the boost pressure exceeds fuel pressure in the carb. I have done alot of homework on this idea for several months now and I am just starting to buy every thing I need. My estimated Hp at 10 psi of boost should exceed 600 hp. This set up will cost less than $3000. once its up and running I post the whole project and include a priced out parts list.Tumarr38805.9162962963

Here is another company that does turbo kits for small block chevy's. This is there 600hp twin kit with two tiny little turbos that sit ontop of the Valve covers. those turbos might be too small for your 383 but I am sure if you talk to them they can give you bigger turbos better suited for your need. here is the Kit
This is a single turbo kit they got. They have arranged the turbo very similar to how I am going to do mine. here is the single KitIn my opinion the single kit would be a better bet for a C3 because uses up much less space. The turbo on that kit is again a little too small for a 383, So he could bump you up to a T-70 or maybe a GT45 turbo for alittle extra money.

Those kits do not include a EFI set up. The TPI intake has been proven to work well for turbo applications though. If you do your home work you will find that a stock ECM in a Tuned port injection car can be modified to work with positive boost. Not stuff for novices though. Good luck with your Car!   Tumarr38805.948275463

Hello, I might be of some Help as I have had a Banks Twin Turbo in my 1980 since 1988. Soon after they stoped producing this Kit and went with the Diesel Truck stuff and now that the Big Three are producing better Diesels there Sales are off so they have re-envented there old Gasoline stuff. I'm in the Process of Modernising my Whole Car and Updating the Engine as well. Forget about the AC problem as there Kit uses a Serpintine Belt and a Small AC Compressor that is produced by Vintage Air. The Vintage Air Kit Bolts Right in to a C3 with No Clearance Problems at all and works very well on a C3 with or with out the Turbo Setup. The only Clearance problem I had was the wastegate is in the way of the Power Steering Tank on the Pump so I had to remote mount it. Keep in mind if You got it from Banks they would allready of worked this out. The other Clearance problem is going to be with the Hood. The Accel Manifold is Tall and no way is it going under. I'm using an original Edelbrock Torker (What Banks Supplied with the old Carb Kit) and I have Machined about 1/2" off the Top to get it under a Low Rise Turbo Hood. I now have the Accel Manifold and will be Using it with my New Engine I have built but that not going till the end of Summer.It might go under a High Rise Turbo Hood. Don't even consider a Carberator on this setup. The best thing that has ever happened to a Turbocharged Engine in the last 20 Years is the ECM. GM hasn't produced a Carberated Engine since 1986. They say that a Carb is nothing but a controled Fuel Leak but on a Blow through System its nothing but a Out of Control Fuel Leak. This was the downfall of the original setup it would run great on a Dyno but not on the Street. As far as other Fuel Injection Brands the Accel is the only way to go as You will need to set the Fuel Curve up to match Your Combination wich cannot be done with the less exspensive brands. My Engine made or Lost 140 HP with Plus or Minus 1.5 degs of Timing. From now on that is all controled by the ECM. I think that if You purchase everything that comes in the Banks Kit seperately that You will find that Your not going to save much at all. Its not Cheap. Also keep in mind that Cars with Staight Axel Rear Ends are ment for Drag Racing and there for Superchargers are Ok but Cars with Independant Rears are ment for Roadracing and that means Turbocharging. Hope this Helps. Richard...

Sorry, I forgot you have a 406 and not a 383 my bad. Either way the same advice still stands, your just gonna need the bigger turbo(s) even more.