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471 blower + 350 sbc

  
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471 blower + 350 sbc

 
clix00 clix00
I love my Chevy Chevette! | Posts: 4 | Joined: 12/12
Posted: 12/24/12
10:07 PM

I got a 83' 350 I've been itching to drop this GM 471 blower supercharger on. What all do I need to look into before doing so? I've found a few places that make an adapter plate so it will bolt to a Weiand 671 intake.

From what I know about the engine is, it has either 8.2:1 or 8.5:1 pistons, a mild cam, and some other work I will find out by digging into it when I get ready to do everything.

Being that it's only a 471 blower, what size carb(s) should I look into? It is built for twin carbs, but I believe I can get a adapter to only run one.

This is a street ride, not a track, and I am only trying to achieve about 8-10b of boost. From what I have heard is about 12% OD will get me that much. I still will be needing to buy the pulleys and what not for it. But trying to find more information, or a competent engine builder to talk to about it.

Any help would be greatly appreciated!  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/25/12
03:57 AM

clix00 welcome to Super Chevy:

1.What is the engine going in?

2.I would use a 8:2:1 Forged Piston. They will handle the beating.

3.I would really install a forged crank and rods with the forged pistons.
I think if you start hanging more pulleys off the nose of a cast crank and the load just to spin even the 471, maybe too much for the snout of the crank.
  The reason I say that a cast crank is going to bend, and eventually fail. With that said.

4.5-6-PSI of boost is really what you want not any more than that for a street engine.

5.Those old 471 started out in the 1950s in fuel cars.

6.A 750CFM carb is enough for the 471 puffer.

7.I've seen the 471 on V-6 engines and live.(Ford Mustangs).

8. In my opinion, I would get a 671 and build a complete different engine assembly, with all the forged bottom end parts.

9.I have a supercharged 3.8 in a 2005 Monte Carlo SS and it will run at 7-8 psi of boost. The gas is the controlling factor today. Even with 93 octane thats all it can handle.
  Its early and Christmas lets see what the other GURUs have to say. Someone may have a different opinion, and know how. I like blowers, I just think the 471 is a little too small. JMO..... Grin  Cool
  MERRY-CHRISTMAS....

Bob  

clix00 clix00
I love my Chevy Chevette! | Posts: 4 | Joined: 12/12
Posted: 12/25/12
09:41 AM

Thanks for the welcome! Long time reader, first time poster!

It will be going in a 83' k20. I'm not looking to go insane with it, but more of a just cause' aspect. The only reason I am leaning on the 471 is because I have one that was recently rebuilt, vs going out and spending the money on a complete new one.

Also the aspect you don't see them very much anymore. From what I have found about them, back in their hay-day, they were the cats a**.

Like I said, I'm not looking to go all out insane on it. Just shooting for "because I can". It does have a forged crank, pistons, and rods, I know that much. Beyond that I'm not 100% sure on.

Edit: forgot to add the block is a 4-bolt main.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/25/12
02:58 PM

clix00

  Oh yeah I remember them. They were the cats arrzz. I myself have been along time reader, I'm guessing 40+ years with some of my car magazines. I started to contribute approx a year ago. I was asked to join the world of the Hobby and Sport I enjoyed for so many years.
   I hope to give back some information and believe this I have learned a lot from my peers also, and some of the younger guys. Have come along with some useful information of their own. I was told once and only once. I was a walking encyclopedia of useless information. Remember I said only once!

 Bob  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/25/12
04:01 PM

clix00

I would stay on the lower end on C/R. I thought I missed something about what you have. Then by all means use that Block.

1.8:2:1-8:5:1 is great.

2.You can use Gapless piston Rings also.

3.A Must to "Balance the Assembly". They sound so sweat when they start whinning into thier power curve. Then hang ON.

4.You didn't mention heads. Do you have something in mind?

5.All kidding aside. When that engine is broken in you'll be jumping on it.

6.Are you doing the building? Or farming it out?

7.Let us know when your ready to go.
Bob  

clix00 clix00
I love my Chevy Chevette! | Posts: 4 | Joined: 12/12
Posted: 12/25/12
09:27 PM

Bob,

1.) That's what I was hoping for, the engine as it sits is pretty new, < 10k on it. so doing a complete tear down I was hoping to avoid. But I do have a 400 sbc that was my other option to play with.

3.) I was going to make sure everything was done right, I can't stand stuff just being slapped on and call it good. Far to much OCD flows through my veins.

4.) I am going to pull whats on it off and see what they are before I move much further. But I have the option of a set of 202/160's a buddy built while he was in mechanic school.

5.) That's the plan!

6.) This truck is my toy. I got a s10 & a GSXR as my daily. I've always had a thing for 60's-sub 87' trucks super charged. My goal is to trying and conceal the charger as much as I can (trying not to throw a bug catcher on!) without restricting it's performance. I haven't made all the measurements yet, but think I can get by, with at most a 4"-6" cowl. Being the amount of space the k20's have under the hood, I am hoping to make it work being a sleeper of sorts.

I greatly appreciate all of your help thus far! It's been a nightmare trying to find anything out. Most of these engine builds around me don't want to tell me anything unless I plan on letting them do the work, so they can cash in on that fat check! Can't say I blame them much in this economy now though!

Any idea's on someone based in the US that would be able to get me an intake and/or adapter plate for this antique? Same with drive pulleys.

Thanks again,
Will


EDIT: Also I would like to add a bigger cam in it while doing all of this since I'll have it apart. Any suggestions on which way to learn there? I low the rough idle, and I don't got to worry about a converter since it is a 4 speed.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/26/12
01:56 AM

Will

Your going to have to try these guys.www.superchargers.com   www.edelbrock.com
See if they can help you with all the accessory parts. Thats why those are reliics.

4.As long as the heads are not less then 72cc.

6.The K-20 should have some room, not much you can conceal about those. They whine also. Of course you can tell people its a noisy gear drive.

The best cam to use today is an Hydraulic Roller. You don't have to worry about rubbing a Lobe off. More expensive to start, but down the road they do a lot of things right.

Bob  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/26/12
08:08 PM

Will

www.cartechbooks.com  They have a book on Street SuperCharging.

Thier books are well written and very informative. I would start there. They may

have references to get parts.

Bob  

tuffnuff tuffnuff
Moderator | Posts: 268 | Joined: 01/10
Posted: 12/27/12
03:36 PM

A 4-71 is a bus blower that was never designed to be over driven.,. diesels max out at about 2800 R's.
Your intention of over-driving it will create issues, above 3500 R's add to that over drive.
Get a 6-71 and under drive it 7/8% and you'll get 6/7 pounds of boost with reduced adibiatic temp spikes.
Heat offsets any boost gained.,. real quick.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 12/29/12
01:02 AM

Tuff:
Thanks for clearing that up. I knew the T/F of yester year used them but under drove them (Bad wording) thats why they never made good power or where used. I was having a heck of a time finding info on them.

"HAPPY NEW YEAR"
Bob  

tuffnuff tuffnuff
Moderator | Posts: 268 | Joined: 01/10
Posted: 12/30/12
10:48 AM

No problem Bob and you welcome.,. the old blowers had roller bearings that were never designed for high RPM applications.,. too much surface speed.

Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder