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Old 05-16-2013, 12:16 AM
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6-71 Blower Set-up!

Hey guys! Havent been on here in awhile. Im going to get to doing this blower set up on my 350 . I want to go .30 over and get all the internals right for it. This is what I got on my list so far.

CAM Crowler Camshaft, Hydraulic Roller, Advertised Duration 273/284, Lift .525/.545, w/ Roller Rockers/lifters

ROTATING ASSEMBLY. Eagle Specialty Products 35100030 - Eagle Forced Induction Competition Rotating Assemblies
Piston Material:Forged aluminum
Piston Styleish, with a D-shaped cup
Piston Head Volume (cc):+22.00cc
Crankshaft Material:Forged 4340 steel
H-Beam Rods

HEAD GASKET Head Gasket, Composition Type, 4.166 in. Bore, .041 in. Compressed Thickness

CaRBS Holley 4150 blower carbs. Now im thinking about 2-600 but I have also seen 2 750s? Which to go with?

HEADS RHS Cylinder Head, Pro Action, Aluminum, Assembled, 72cc Chamber, 200cc Intake Runner
ELECTRICAL is all MSD pro billet dist., small diam. cap/race rotor/Blaster ss coil/ MSD 6-BTM CD Ignitions
Of course the 6-71 polished blower new from summit. and cant forget the supercharger manual on how-to


Now as far as what I have, what else would I need guys? I have listed a 170gph/8psi mechanical f.p. Do I need a electric? I have the compression down to 8.2 I believe (if someone could double check me that would be great). Do I need to buy an actual a/f ratio gauge or will just getting this tuned be fine after its all runnin? Appreciate it guys!!

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Old 05-16-2013, 12:47 AM
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Assuming the pistons are 1.560" compression height, the rods are 5.703" and the crank radius is 1.742", then you have a stack of 9.005". You will need to use a composition gasket with a pre-flattened fire ring to prevent brinelling the heads, and the gasket needs to be around 0.040" thick (0.039"/0.041"). Have your machine shop check the main bearing bore for being round and parallel with each other. If the bore is off, correct it to round and straight by either align-honing or align-boring the bore. Then, jig the block up on the mains and cut the block decks to 9.005" This will result in a zero deck, with the thickness of the head gasket providing the squish dimension of 0.041".
728 cc's in the cylinder
72 cc's in the combustion chamber
22 cc's in the piston crown
9 cc's in the gasket
0 cc's in the piston deck height
Total value....831 cc's
Deduct the cylinder cc's from the total and find 103 cc's
Divide 831 by 103 and find 8.07:1 static compression ratio.
8.07:1 static compression ratio will support 8 lbs of boost on pump gas.
To reach 8 lbs of boost with a small-bore 6-71 on a 355, run a 1.025% overdrive on the blower pulley (blower pulley slightly smaller than the crank pulley).
Read all the recommendations and tech info here.....
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service
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Old 05-16-2013, 10:30 AM
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That link helped. Thanks. I was a tad off on the CR but I'm within the range. Will that cam be fine? And the carbs. 2 600 be good or do I have to have he 750s
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Old 05-16-2013, 10:33 AM
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Oh and I will make sure the block is within the spec.
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Old 05-16-2013, 03:07 PM
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Just me,but I think you would be living on the edge with .060 over ,,thin walls with boost,,possible over heating,Check out BDS blower drive services for recommendations.
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Old 05-16-2013, 04:20 PM
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When did I ever say I was going .060 over? I said .030 from stock!
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Old 05-16-2013, 05:11 PM
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My bad ,I was looking at head gasket.4.160,?

Last edited by 496CHEVY3100; 05-16-2013 at 05:21 PM.
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Old 05-16-2013, 07:10 PM
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No Problem!
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Old 05-17-2013, 10:31 AM
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Bump anybody?
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Old 05-18-2013, 09:51 AM
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You didn't give the specs on the cam, advertised lift and duration doesn't tell us much. What is the LSA? The best advice I can give you is to spend a few extra bucks and have a cam custom ground for your goals. It is money well spent. If you want a hyd roller I would suggest getting ahold of Chris Straub here: Welcome to Straub Technologies. . .The Source of Performance.

How much power are you trying to make? If you're putting a 6-71 on it why restrict it with 600cfm carbs. Let it breathe, don't restrict the inlet side of the blower. Put the 740's on it. Now if this is just a street rod type of application, then smaller carbs will be fine, but if you want all the potential then step up and don't put Edelbrock/Carters on it.

As far as head gaskets go, cut your losses and go with a MLS gasket, Fel-Pro or Cometic. Those boost/compression charts are not to live and die by, they are a good reference and starting point that's about it. Too many factors will come into play with a given engine for those charts to apply to every build.
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Old 05-18-2013, 06:39 PM
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I'm not going to a specific power. It's just a street truck that will see the track a few times. I think the 600 will do just fine. That cam I think will be great. I've ran it by some others. The head gasket is a felpro
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Old 05-18-2013, 08:05 PM
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Quote:
Originally Posted by jaeger_bombs View Post
CAM Crowler Camshaft, Hydraulic Roller, Advertised Duration 273/284, Lift .525/.545, w/ Roller Rockers/lifters
You made me go looking for the cam. I suppose this is it....
http://www.summitracing.com/parts/cr...make/chevrolet
If you fellows would just give us the mfg and part number, it would save a lot of time when we're trying to help you.
I see that you have mistakenly chosen a cam with a 114 degree lobe separation angle. If you'll go to the experts on blowers, Blower Drive Service, they will tell you plainly that a 110 lobe separation angle works best on gasoline, a 114 will work better on alcohol. You see, this is like one of those urban legends that gets started. Guy A tells Guy B that he is making X hp on alcohol with a 114 cam. Now, every time Guy B recommends a cam to a blower guy, he mouths the 114 part, but forgets about the alcohol part.
Gasoline 110 degree lobe separation angle works best.
Alcohol 114 degree lobe separation angle works best.

Quote:
Originally Posted by jaeger_bombs View Post
ROTATING ASSEMBLY. Eagle Specialty Products 35100030 - Eagle Forced Induction Competition Rotating Assemblies
Piston Material:Forged aluminum
Piston Styleish, with a D-shaped cup
Piston Head Volume (cc):+22.00cc
Crankshaft Material:Forged 4340 steel
H-Beam Rods
Do your due diligence in measuring all the pieces. These are Chinese cranks and rods and those fellows are not known for precision work yet.

Quote:
Originally Posted by jaeger_bombs View Post
HEAD GASKET Head Gasket, Composition Type, 4.166 in. Bore, .041 in. Compressed Thickness
Again, a mfg and a part number would eliminate wasting my time. Strongly advise using Fel-Pro 1003 which has pre-flattened fire ring.

Quote:
Originally Posted by jaeger_bombs View Post
Now as far as what I have, what else would I need guys? I have listed a 170gph/8psi mechanical f.p. Do I need a electric?
Carburetors in general will not tolerate that much fuel pressure. They were not designed in the first place to tolerate high pressure. Limit fuel pressure at the carburetor inlet to 5 psi maximum. Additional fuel pressure will unload the needle and seat in the bowl and allow the fuel pump to blow raw fuel into the blower, creating a tuning nightmare.
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Old 05-18-2013, 08:13 PM
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Quote:
Originally Posted by jaeger_bombs View Post
I'm not going to a specific power. It's just a street truck that will see the track a few times. I think the 600 will do just fine. That cam I think will be great. I've ran it by some others. The head gasket is a felpro
Sounds like you got it all figurd out. Good luck let us know how it runs.
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Old 05-19-2013, 02:42 AM
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I really appreciate the help tech! So 110 is a better love for gasoline. Roger! And yes I got the fuel system all worked out since my OP. will make sure i check those parts.
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