Blower for SBC

[BK]

I'm thinking of putting a supercharger on my SBC. A 6-71 should do what I want. Doesn't have to be state of the art but I would like it stripped. Would also need an intake with water ports and a drive setup. I should be all set with a hat and fuel system. Send me PM if you have something to look at. Thanks.

[GlennLever]

Sounds like another Steve convert?

[dreracecar]

Stay away from anything tricker than a simple sealed and stripped 6-71, Standard openings top and bottom work fine, all the fuel run thru the hat  only.  Set back manifolds are a waste and expensive. This setup is what I currently run and always in the top 5 of qualy running 7.0pro. Your biggest issue is the crank snout not being stout enough

[GlennLever]

Crank snout should be ok with a mild 6 71 I would think.

Just don't overdrive it a lot.

I'm running a 8 71 on a Pontiac snout with no problems yet.

[dreracecar]

A stock snout can work, but you will have to purchase a front hub from ATI that is for a SBC snout but the OD is is the larger BBC.  There is not enough material from the keyway to the SBC hub seal surface and will split the hub along the keyway and roll the key out of the crank(junking the crank), and the whole mess tears up the front cover. Glenn, I have seen this happen with running underdrive also.

[BK]

Is the stock SBC OD. an issue if you use two keys?

[George]

Yes it is. We built a BBC OD hub to fit the SBC crank and built a support for it .

[Van]

I have everything needed. I have 3  671's all just built by Moneyham, a new blower manifold, everything is full polished, I even have a new 3.750 stroke crank with a Hemi snout & I have the blower hub. If you are seriously looking call me, just PM me & I will send my PH # Also I have a large selection of 1/2 pitch pulleys & belts. Idlers too.

[BK]

In my search for a blower I've run into a really good deal on a new Wiend 6-71 kit. Because of the motor I'm only looking for a few pounds of boost. But I'm sure there are reasons why you don't see them raced. So I have questions and would like input.
Any chance it will stay together Bracket racing?
Will the raw aluminum case and rotors be OK with the fuel? I plan on putting all the fuel (alcohol) in at the hat (Bug Catcher).
It has straight rotors. Will they make any boost and hold up to maybe 7,000 RPM at the blower? 
Would the straight rotors tend to spread the air out more even than the twisted rotors?
The motor is a stock block 355. Steel GM crank. Steel H beam rods. SRP pistons. Compression will be between 11 and 12 to 1. Brownfield heads with 207cc intakes ports. I may need to rethink the 108 lobe sep. on the cam.

[dreracecar]

Not that good of an idea. A race blower is set up and clearenced by someone who knows what he is doing. Set up wrong and without hard anodizing and high speed balencing, if the rotors were to touch each other they would gaul and transfer metal between them and create seriuos problems. They can get away with that on the street because the OD persentage is low, not in boost mode for the majority of time and that gasoline acts as a lubricant, My feeling is that it is a recipe for disaster

[wideopen231]

IMO you are pushing luck if running much boost at all.Gm block and crank with 12:1 and blower.If you feel big bump under butt it could be crank. Anything more than 8 or 10 lbs would worry me with that combo. I would go lower compression with good performance crank and rods. If using GM block I would have  to go to new splayed caps. May be over kill to some,but you are riding behind the engine.

[BK]

Not that good of an idea. A race blower is set up and clearenced by someone who knows what he is doing. Set up wrong and without hard anodizing and high speed balencing, if the rotors were to touch each other they would gaul and transfer metal between them and create seriuos problems. They can get away with that on the street because the OD persentage is low, not in boost mode for the majority of time and that gasoline acts as a lubricant, My feeling is that it is a recipe for disaster

Thanks for the input. I had a feeling that would be the case.

[BK]

IMO you are pushing luck if running much boost at all.Gm block and crank with 12:1 and blower.If you feel big bump under butt it could be crank. Anything more than 8 or 10 lbs would worry me with that combo. I would go lower compression with good performance crank and rods. If using GM block I would have  to go to new splayed caps. May be over kill to some,but you are riding behind the engine.

Because of what I have to work with I was even thinking I would go to 10 lbs.

[ricardo1967]

In other hand... how many hundreds of SBC engines were topped with a 6-71's before specialty block and cranks were made available (or affordable)?

(However, I consider using an aftermarket block for my next SBC, given that the starting price tag ($1.5K) is not too bad considering all the work to prep a production block.)