SBC to BBC - The 1947 - Present Chevrolet & GMC Truck Message Board Network

danho · 12-16-2003, 12:01 PM

I know it's probably been asked a 100 times already, but what do I need to switch from a sbc to a bbc? I might be getting a good deal on a 454 so i'm thinking of scrapping the 383 idea.
This will be going in a 72 k20 cheyenne super with A/C, TH-350, NP205 yadda yadda.
Thanks, Dan.

danho · 12-16-2003, 09:05 PM

t

Tx Firefighter · 12-16-2003, 09:19 PM

I'm in the middle of a big block conversion right now myself. It's been somewhat of a struggle, mainly paying for it all. Some parts just can't be found readily and you have to ferret them out.

Of course, a big block is going to require a large radiator if you don't already have one.

The engine mounts are going to be an issue too. As I'm sure you already know, 4 wheel drive trucks didn't come with big blocks, so there are no factory correct setups.

Plan on spending pretty big bucks to get all of your brackets and pulleys. The AC brackets typically go for 200 per set. I'd plan on 5 to 7 hundred dollars for all of the brackets and pulleys and power steering stuff.

Also, budget in the cost of either having your exhaust modified or running a whole new one.

danho · 12-16-2003, 09:30 PM

Thanks, and wow.
Dan.

dinnut · 12-16-2003, 10:37 PM

i saw a complete running 454 with all brackets complete with turbo 400... even had a compressor. complete!! for 800. thats pretty good....

Longhorn Man · 12-17-2003, 12:50 AM

Since you have a 4X4, and as stated before, there were no stock 4X4 big block trucks, you'll be needing to do a body lift from what I understand.
I'm sure there is more to this...like what towers to use?

**Yukon Jack** · 12-17-2003, 11:59 AM

In the 4x4 you can just use your stock small block motor mounts and towers. Might need to adjust a little to move the crossmember forward for oil pan clearance, but the engine stays in the same location. Generally, a body lift will help, but I have heard some people get away without one.

**Bernie** · 12-17-2003, 05:43 PM

I thought about putting a BB in my K20. I was told that it could only be done if the motor was moved forwards. In a 4X4 the motor is in the 6 cylinder position. The reason for having to move it is that the BB is wider than the SB and the indent in the firewall is too narrow to hold it. I tried tall valve covers on a SB and didn't have enough room for them so I could beleive what I was told.

12-16-2003, 12:01 PM	#1
danho Pesemistic Optimist Join Date: Dec 2002 Location: Prineville, Oregon Posts: 227	SBC to BBC I know it's probably been asked a 100 times already, but what do I need to switch from a sbc to a bbc? I might be getting a good deal on a 454 so i'm thinking of scrapping the 383 idea. This will be going in a 72 k20 cheyenne super with A/C, TH-350, NP205 yadda yadda. Thanks, Dan.

12-16-2003, 09:19 PM	#3
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I'm in the middle of a big block conversion right now myself. It's been somewhat of a struggle, mainly paying for it all. Some parts just can't be found readily and you have to ferret them out. Of course, a big block is going to require a large radiator if you don't already have one. The engine mounts are going to be an issue too. As I'm sure you already know, 4 wheel drive trucks didn't come with big blocks, so there are no factory correct setups. Plan on spending pretty big bucks to get all of your brackets and pulleys. The AC brackets typically go for 200 per set. I'd plan on 5 to 7 hundred dollars for all of the brackets and pulleys and power steering stuff. Also, budget in the cost of either having your exhaust modified or running a whole new one. __________________ I'm on the Instagram- @Gearhead_Kevin

12-16-2003, 10:37 PM	#5
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	i saw a complete running 454 with all brackets complete with turbo 400... even had a compressor. complete!! for 800. thats pretty good.... __________________ 70 longbed 496/th400/Ford 9"

12-17-2003, 11:59 AM	#7
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	In the 4x4 you can just use your stock small block motor mounts and towers. Might need to adjust a little to move the crossmember forward for oil pan clearance, but the engine stays in the same location. Generally, a body lift will help, but I have heard some people get away without one. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

12-17-2003, 05:43 PM	#8
Bernie Senior Member Join Date: Jan 2001 Location: Northern Illinois Posts: 516	I thought about putting a BB in my K20. I was told that it could only be done if the motor was moved forwards. In a 4X4 the motor is in the 6 cylinder position. The reason for having to move it is that the BB is wider than the SB and the indent in the firewall is too narrow to hold it. I tried tall valve covers on a SB and didn't have enough room for them so I could beleive what I was told. __________________ Bernie

12-16-2003, 09:05 PM	#2
danho Pesemistic Optimist Join Date: Dec 2002 Location: Prineville, Oregon Posts: 227	t

12-16-2003, 09:30 PM	#4
danho Pesemistic Optimist Join Date: Dec 2002 Location: Prineville, Oregon Posts: 227	Thanks, and wow. Dan.

12-17-2003, 12:50 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Since you have a 4X4, and as stated before, there were no stock 4X4 big block trucks, you'll be needing to do a body lift from what I understand. I'm sure there is more to this...like what towers to use?

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