I need a blower for a 351C/351M/400. Does anyone know where to find one? I asked scavenger place for the BDS blower and they don't carry it, nor have the ever carried it. I notice that Ghost312 is also lokig for one or acts like he knows where to find one for a 351C. I would even take one for a 351C.

Thanks

 

BDS has a couple go to their website(i think www.bds.com if thats not it do a search for it i also think vortech might be one to , not sure though.


82' Flareside with 400 horse under the hood

 

www.bds.com gets you Black Daimond Software's website. I doubt you'd find a supercharger there.

 

http://www.blowerdriveservice.com/

 

I just saw one on ebay for the 351C..

"Polished blower setup for a 351 cleveland. B&M manufacture. VERY hard to find for a cleveland motor. Buyer pays all shipping&handling. Cert ck. or money order ONLY!!!!!!!!!!I reserve right to end auction at any time!!!"
Item # 1818547259

Just wish I could use one of these in my class ..

 

I checked into blowers before I built this engine. I finally gave up on the idea because on a streeter it's really hard to do. In addition to the manifold problem you may have clearance concerns with the distributor and some real head aches trying to line up a drive pulley with all the accessories involved.
There are no kits made that I know of for this engine. You might have better luck with something like a Ken/Bell that bolts onto the existing carb mount.

Bear

 

the website http://www.racesearch.com has a root type supercharger for the 351c and the 400 go to this link if youd like to check it out kinda pricy at like upwards of 3k but hey i thought i would help
http://www.racesearch.com/CGImp/mhp?man=0&sort=PRICE&engtype=113&Try+Again=Try+Aga in&mode=sbpn&cat=2488:-staun

 

http://www.racesearch.com/CGImp/mhp?man=0&sort=PRICE&engtype=113&Try+Again=Try+Aga in&mode=sbpn&cat=2488

there sorry my little graphic got in the way

 

bds actually makes one to fit the 400 block

 

Does the 400 really need a 871 blower? The rating means that the blower is sized for an 8 cylinder Detroit Diesel with 71 cubic inches per cylinder. Which means that blower was meant to feed 568 cubic inches with boost. I'd think the 400 couldn't be taken over 4 to 6 psi of boost safely without major interior mods so you'd just be underdriving the hell out of that thing. It seems that the 671 blower would be more closely matched since it feeds a 426 cubic inch diesel.

You're not going to take a street 400 over 5200 turns very often. I was thinking about maybe 1 to 2 psi of boost would be plenty on this torque monster. Desk top dyno says that'll make nearly 800HP and 1000ft-lb of torque under 4000RPM.

Anyway, enough of me thinking, i just get into trouble when i do that. It just seems that an 871 should be on a 460 spinning over 6000RPM.

 

[updated:LAST EDITED ON 02-May-02 AT 00:06 AM (EST)]>You're not going to take a street 400 over 5200 turns very
>often. I was thinking about maybe 1 to 2 psi of boost would
>be plenty on this torque monster. Desk top dyno says that'll
>make nearly 800HP and 1000ft-lb of torque under 4000RPM.

You're going to take a mildly modified 400ci gasser and put 1-2 psi of boost on it and end up with a 1000 ft lbs of torque. No. Sorry, that won't happen in real life.

Maybe you're thinking diesels, but not on a gas plant. I'd say 450-650ftlbs is your range depending on boost.

 

>Does the 400 really need a 871 blower?

no it does not need a 871 blower, but does it want one, well hell yes.

gees

 

That 1000ft-lbs looked wrong to me when the program spit out that graph. But it is nice to dream of smoking all 4 tires on concrete.

I'm looking to get 500ft-lbs with a holley 750 at 30 ft below sea level. One of the advantages to living in New Orleans.

 

[updated:LAST EDITED ON 03-May-02 AT 07:39 PM (EST)]Fact Number 1 All positive displacement forms of intake (anything that runs off boost) increases air temperature. This is a fact of physics that cannot be escaped. All compressed gasses release heat. If you don’t think this is true grab the top of a running air compressor pump sometime.

Fact Number 2. Turbo Charging is from 75 to 100% more efficient than any form of supercharging other then Nitrous Oxide. This is because all forms of supercharging are run off the crankshaft. Because of this they use part of the power they generate to operate. On smaller systems such has the B&M 144 CID, and Paxton’s centrifugal force models, this can be as little as 25%. While on larger systems like the famous 6/71 will use as mush as 50% to 70% of the power they make to compress the air.

Fact Number 3. Turbo Charging uses no direct power from the engine period. This is what makes turbo charging more efficient then supercharging. Turbo’s are powered by the engine exhaust Thus no power loss.

Fact Number 4. You do not need high rpm’s to get large amounts of boost from a turbo charger. You do need a large turbo to get low rpm boost though. The majority of semi’s run turbo chargers and these engines never see over 3000 rpm’s, yet they can have over 30lbs of boost.

Fact Number 5. All roots style superchargers are rated by their displacement and not the number of cylinders of the diesel engine it came off of. The 6/71 got it's "name" because when those hot rodders in California figured out that you could make one of these lungs fit on a V8, it was the charger off the 6/71 Detroit engine that was right size to fit on top of the Ford Flat Head v/8. The truth is even 6/71 blowers can have differnet CID (and thus) power ratings. The terms 6/71, 8/71, 10/71 and so on are used to describe the case size only.


There are three different kinds of superchargers. One is the centrifugal (Paxton), the second is the root’s (GMC) style and the third is the Whipple Screw Compressor. The GMC style roots type BDS (blower drive systems) and the Whipple are what is know as a positive displacement blowers. These systems use a housing that you see mounted on top of the engine. When you hear someone say they have, for example, a 132 or 176 cid blower they are talking about the amount of displacement that is inside this housing. Roots street system use two or three vanes that are turned by a very large belt connected to the crankshaft. These vanes have the same job as the piston inside the engine. They compress the air moving through the case and into the engine. This is how the blower develops boost, by forcing the volume of trapped air inside the blower housing into the engine. A Whipple uses the same kind of housing but compresses the air by the use of 2 “screws”. These screws are much like to pinion gears that intermesh. It’s the intermeshing action that makes the boost.


The centrifugal can be looked at as a turbocharger that runs off the crankshaft instead of the exhaust. Air is drawn in the center of the charger by a small fan spinning at very high speeds, just like a hairdryer. It’s the force behind the air that makes the boost. The only difference between the centrifugal force charger and the turbo charger is that the turbo works off the exhaust and is not gear driven by. Because the centrifugal force chargers fan must spin a very high speeds to make boost it has to be gear driven and this combined with the compression of the air robs the engine of power.

Turbo Charging:

A turbo charger runs off the exhaust of an engine. They work much the same way that old fashion waterwheels did. The gas that exits the exhaust port is traveling at near, and sometimes over, the speed of sound. This makes for a great place to regain lost energy and the turbo does this by inducing compressed air back into the engine. The turbo works much the same way as the centrifugal blower described above, but with one big difference. They are not gear driven.

In fact in all turbo’s there is only 1 moving assembly. This assembly is made of three parts. The exhaust rotor, the rotor shaft and the intake rotor. The rotors used in a turbo look very much like the intake fan on a household vacuum cleaner. The reason why they are this design is because this is the most efficient design to use that does not create “prop wash”. Prop wash is when the air gets moving past the blades so fast that the blade loses it bite. When this happens the blade is no longer able to move air. If you have ever spun an outboard boat around in the water to fast you know what I am talking about.

Turbo’s spin at very high rpm’s and some may reach over 250,000 rpm’s at full boost. They need to spin this fast because they have very small intakes. On the 231 Buick V6 for example the early models only had 2.2” openings. That means the turbo is trying to feed an engine that is 100 times it size in volume. As the engine speed increase the turbo must gain rpm’s very rapidly to keep up. This is where turbo lag felt.

In the mid 80s Garrets, the OEM supplier to Ford and GM, came up with a new fan design that broke the exhaust rotor fins into 3 separate attack angels. This new design, combined with the use of ceramics that made the blades 75% lighter, has lead to turbo’s that have less then a .05 of a second reaction time from negative boost (vacuum) to full boost (20 psi).

I own a 1983 Buick Regal T-Type Turbo Coupe with the old style turbo. I also belong to the National Turbo Regal Club. I’ve had several chances to ride in the 1986 and 87 coupes with the new turbo and the difference in response time between the two models is unreal. This also illustrates the difference between a positive displacement supercharge and a centrifugal force model.

As soon as the engine starts to rotate (even before it fires) a positive displacement supercharger is feeding the engine boost. If you recall from the post above, what a roots style blower does is basically add CID to your engine. For example, lets say you added a B&M 144 CID to your 351M. Your relative displacement is now 495 CID! This also increases your compression because you are basically trying to shove the extra volume of the blower into the cylinder. But engines love boost and most street engines can run from 32 to as much has 50* of timing advance with no troubles.


Where a roots type uses displacement to increase the cylinder pressure a centrifugal force blower (Paxton or turbo’s) use massive pressure. When a roots is trying to shove its 144 cid into a cylinder at 6 psi, a centrifugal blower is trying to force in extra air by injecting it into the cylinder under more pressure. Think of the roots type as a bucket. Turn it over and all the water falls out at high volume, but at low pressure. The centrifugal is a fire hose. Turn it on and it’s going to pump five gallons as fast as it fell out of the buck. The difference is the buck had high volume low pressure and the hose had low volume but at high pressure. The end result is that they both moved 5 gallons at the same transfer rate. In our 351 this means that they both would fill the cylinder with the same amount of air, just that the blower did it by pushing a high volume at low speed and the centrifugal did it with low volume but high speed.

When you hear someone talking about cooling the intake charge they are talking about running the compressed air through an After Cooler before it reaches the intake manifold. This cools the charge and helps make more power and also helps prevent ping. You can run one with any blower set up but the most common use for them is with the centrifugal style compressors (Paxton and turbo’s).

You do have to tune your carb or F.I. to run with a blower. First is for the obvious reason that you are increasing the demands for fuel. The second is because the intake charge is so hot that fuel can actually over vaporize and hit a very lean condition. 99% of the time you see a hotrod with a blower pulled off the to the side of the road his troubles is from vapor lock in the blower. Been there and Done that one to many times.

There is a lot more then I can share on blower engines, from detailing cam profiles to compression ratios and port design. But I think this gives a good basic overview of how each of the three more common systems work. If someone is serious about wanting to choose between a supercharger, or a centrifugal force blower, I’ll be more then happy to go over the complete pros and cons of each system and help them figure out what they need to make a strong and reliable thumper engine.

Blown Engines I’ve owned in the past

383 SBC 144 CID B&M o% drive
427 BBC 227 CID BDS Case 30% Over
455 Buick G-Force G5 Machined Case S-3 Drive System 7.1” Super Fly
350 SBC Paxton S-3 Factory Vette Kit
231 Buick Garret t-2 Second Generation