Big Block shroud measurements - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blue68 · 06-25-2002, 02:49 PM

Can someone tell me the measurements on a Big block fan shroud. I'm looking for the diameter of the fan opening and the depth from the core to the back lip of the fan opening.

It's my understanding that the core dimensions (mounting points) are the same for BB and SB. Right?

Bill72BB · 06-25-2002, 03:19 PM

Depth 4 3/4 " . 21" Dia

Bill

Blue68 · 06-25-2002, 03:28 PM

Gracias.

Blue68 · 06-27-2002, 06:09 PM

One more question, does it look like it would be possible to cut about an inch off the fan opening without getting into the flattened area? My fan sits about 2.5 inches off the core so I'd be looking for the fan opening to be about 3.5 inches from the core.

I'd like to avoid trying to build a shroud, and I don't have access to a big block shroud I could test fit and take some measurements with before buying. While electric fans are fine, I still like the mechanical and don't mind the hp drop.

Bill72BB · 06-27-2002, 06:56 PM

Blue;
Not sure what you are thying to do ?

My fan is 2 1/2 " from the core also and is almost completely into the shroud .

There is about 1 1/4" you can play with B4 getting to the flat part
but I think you would be defeating the purpose of the shroud .

Good Luck

Bill

Blue68 · 06-27-2002, 07:23 PM

Sorry, I should explain a little better. I've swapped out the engine and accessories with a '98 engine and accessories, including the serpintine drive and fan. It is a 19" fan so the 19" hole on the SB shroud isn't large enough. I'm trying to determine if a BB shroud would work so I can maintain a stock look (granted stock between 30 yrs). I really want to run the larger fan.

At 4 3/4, my entire fan would be inside the shroud. The blade depth is only 2 inches.

2 1/2 front of blade, 3 1/2 middle of blade and 4 1/2 back of blade. I've read that you want the blade half in the shroud for best performance. The source is the www.Flex-a-Lite.com FAQ. Of course, there isn't an electric fan on a stock vehicle out there that isn't fully shrouded.

06-25-2002, 02:49 PM	#1
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	Big Block shroud measurements Can someone tell me the measurements on a Big block fan shroud. I'm looking for the diameter of the fan opening and the depth from the core to the back lip of the fan opening. It's my understanding that the core dimensions (mounting points) are the same for BB and SB. Right? __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

06-25-2002, 03:19 PM	#2
Bill72BB Thats the Hillbilly way Join Date: Jul 2001 Location: Torrance,Ca Posts: 5,979	Depth 4 3/4 " . 21" Dia Bill __________________ BILL Torrance Calif 90504 Member DUF Club Member Old Farts Club 72 3/4ton Custom Camper BB402/400 trans Dynomax Cerama-coat headers , Hei distributor ,Edelbrock 1411 air,ps,pb,leafsprings ,98 chevy 60/40 seat,S10 shoulder belts tilt,3.54 Dana 60 rear. 16" Eagle wheels with LT265/75 16 tires,Gaylord Lid,H4 headlights with 100W relay conversion. " If I knew I was going to live this long I would have taken better care of myself " Marriage changes passion...suddenly you're in bed with a relative. A GUY'S PRAYER.... Lord, I pray for a nympho with huge boobs who owns a liquor store and likes to fish and hunt and has a Harley .Amen ,

06-25-2002, 03:28 PM	#3
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	Gracias. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

06-27-2002, 06:09 PM	#4
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	One more question, does it look like it would be possible to cut about an inch off the fan opening without getting into the flattened area? My fan sits about 2.5 inches off the core so I'd be looking for the fan opening to be about 3.5 inches from the core. I'd like to avoid trying to build a shroud, and I don't have access to a big block shroud I could test fit and take some measurements with before buying. While electric fans are fine, I still like the mechanical and don't mind the hp drop. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.

06-27-2002, 06:56 PM	#5
Bill72BB Thats the Hillbilly way Join Date: Jul 2001 Location: Torrance,Ca Posts: 5,979	Blue; Not sure what you are thying to do ? My fan is 2 1/2 " from the core also and is almost completely into the shroud . There is about 1 1/4" you can play with B4 getting to the flat part but I think you would be defeating the purpose of the shroud . Good Luck Bill __________________ BILL Torrance Calif 90504 Member DUF Club Member Old Farts Club 72 3/4ton Custom Camper BB402/400 trans Dynomax Cerama-coat headers , Hei distributor ,Edelbrock 1411 air,ps,pb,leafsprings ,98 chevy 60/40 seat,S10 shoulder belts tilt,3.54 Dana 60 rear. 16" Eagle wheels with LT265/75 16 tires,Gaylord Lid,H4 headlights with 100W relay conversion. " If I knew I was going to live this long I would have taken better care of myself " Marriage changes passion...suddenly you're in bed with a relative. A GUY'S PRAYER.... Lord, I pray for a nympho with huge boobs who owns a liquor store and likes to fish and hunt and has a Harley .Amen ,

06-27-2002, 07:23 PM	#6
Blue68 Registered User Join Date: Apr 2000 Location: Frisco, Tx, USA Posts: 606	Sorry, I should explain a little better. I've swapped out the engine and accessories with a '98 engine and accessories, including the serpintine drive and fan. It is a 19" fan so the 19" hole on the SB shroud isn't large enough. I'm trying to determine if a BB shroud would work so I can maintain a stock look (granted stock between 30 yrs). I really want to run the larger fan. At 4 3/4, my entire fan would be inside the shroud. The blade depth is only 2 inches. 2 1/2 front of blade, 3 1/2 middle of blade and 4 1/2 back of blade. I've read that you want the blade half in the shroud for best performance. The source is the www.Flex-a-Lite.com FAQ. Of course, there isn't an electric fan on a stock vehicle out there that isn't fully shrouded. __________________ http://home.comcast.net/~r.landrum/w...tos.html-.html '68 C-10 LWB, '98 Z-71 350 w/accessories (Serpentine), Edelbrock Performer, Edelbrock 1405 (600cfm) carb, GM HEI, CompCam Extreme 4x4 roller cam, Thorley Headers, Carter Electric Fuel Pump, Vintage Air, 700r4, 3.73, disc brakes and power steering upgrades.



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