Small block to a big block - The 1947 - Present Chevrolet & GMC Truck Message Board Network

WakBordr7387 · 05-02-2006, 02:21 PM

On my 86'SWB, It originally had a 305 in it, which was replaced with a 350 and now Im about to replace that with a big ass 454. I know the transmission will mount up just fine, along with the motor mounts and getting a new radiator to cool all those inches.
Will the stock pulley's for a small block fit the 454? and is there anything else I need to swap out for the 454 to fit right?

SSC's76 · 05-02-2006, 02:39 PM

The pullys and brackers are different so your going to need them also. Some people have modified some SBC brackets to fit a BBC but it would probably be easyer to buy them then attepemt to make brackets and spacer to mount the pullys.

86 GMG · 05-02-2006, 03:08 PM

it would easier and a lot safer in my opinion to get the bbc stuff like SSC said

rockman20 · 05-02-2006, 03:47 PM

Dumb question maybe since I don't know about your project. What have you done with the front suspension? Is it ready for that extra weight?

WakBordr7387 · 05-02-2006, 04:34 PM

Thanks guys, Ill see if I can't find a truck that had a big block in it and steal the pulleys and all that off of it.
I completly forgot about the extra weight, and I haven't touched the suspension. Do you think I need new springs or anything else?

SanitysBane · 05-02-2006, 07:08 PM

Only if you feel like it. When I put in a big block in my truck I used the factory small block springs. It sat down maybe 1/2inch lower.

Bad Karma · 05-02-2006, 07:29 PM

Get a bigger fuel tank.

C&C Chevy · 05-02-2006, 11:04 PM

Funny, I was just about ask a "How to go from a smallblock to a v-6" thread!

**N2TRUX** · 05-03-2006, 12:36 AM

When you find the BB truck get a few more parts besides the pullies and brackets. You will need the radiator cover, fan shroud, and radiator mounting rubbers to make that four row wide core radiator fit.

f.monroe · 05-03-2006, 10:49 PM

You probably know this but I would check the flexplate against the torque converter before you drop the BigBlock in . I think there are two different bolt patterns on some flexplates and or some torq converters . The 454 uses an externally balanced flexplate , and the 305/350's are internally balanced ,so I am sure you will be using a different flexplate than the one currently installed and it might be worth your time to check the pattern first . Just a thought . Frank

05-02-2006, 02:21 PM	#1
WakBordr7387 Registered User Join Date: Jun 2005 Location: Corpus Christi, TX Posts: 45	Small block to a big block On my 86'SWB, It originally had a 305 in it, which was replaced with a 350 and now Im about to replace that with a big ass 454. I know the transmission will mount up just fine, along with the motor mounts and getting a new radiator to cool all those inches. Will the stock pulley's for a small block fit the 454? and is there anything else I need to swap out for the 454 to fit right? __________________ 86' C-10 Silverado 85' C4 Corvette When in doubt, BURN OUT!!

05-02-2006, 02:39 PM	#2
SSC's76 No No Join Date: Jun 2005 Location: Pueblo Colorado Posts: 1,781	Re: Small block to a big block The pullys and brackers are different so your going to need them also. Some people have modified some SBC brackets to fit a BBC but it would probably be easyer to buy them then attepemt to make brackets and spacer to mount the pullys. __________________ 1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler

05-02-2006, 03:08 PM	#3
86 GMG Registered User Join Date: Apr 2005 Location: Tulsa Oklahoma Posts: 943	Re: Small block to a big block it would easier and a lot safer in my opinion to get the bbc stuff like SSC said __________________ square body trucks an addiction or an investment either way they consume all my extra time and money

05-02-2006, 03:47 PM	#4
rockman20 "The dude abides" Join Date: Apr 2003 Location: North Dakota Posts: 472	Re: Small block to a big block Dumb question maybe since I don't know about your project. What have you done with the front suspension? Is it ready for that extra weight? __________________ RockMan 1993 Chevy Silverado C3500 1 ton dually 1994 Honda Civic 1969 Oldsmobile Cutlass S 1953 IH Farmall Super M New to the fleet: 1992 Subaru Loyal

05-02-2006, 04:34 PM	#5
WakBordr7387 Registered User Join Date: Jun 2005 Location: Corpus Christi, TX Posts: 45	Re: Small block to a big block Thanks guys, Ill see if I can't find a truck that had a big block in it and steal the pulleys and all that off of it. I completly forgot about the extra weight, and I haven't touched the suspension. Do you think I need new springs or anything else? __________________ 86' C-10 Silverado 85' C4 Corvette When in doubt, BURN OUT!!

05-02-2006, 07:08 PM	#6
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	Re: Small block to a big block Only if you feel like it. When I put in a big block in my truck I used the factory small block springs. It sat down maybe 1/2inch lower. __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

05-02-2006, 07:29 PM	#7
Bad Karma Magnificent bastard Join Date: Oct 2004 Location: Glendale, AZ Posts: 196	Re: Small block to a big block Get a bigger fuel tank. __________________ 1977 Big Block Burb

05-02-2006, 11:04 PM	#8
C&C Chevy Registered User Join Date: Feb 2003 Location: Midwest City, OK Posts: 1,001	Re: Small block to a big block Funny, I was just about ask a "How to go from a smallblock to a v-6" thread! __________________ Robert Current: 1986 SWB Silverado 4.3 / TH400 Past: 1985 SWB Silverado 305 / TH350 - sold 1995 1987 1/2 ton Silverado - FI 350 / 700R4 sold 2007

05-03-2006, 12:36 AM	#9
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,021	Re: Small block to a big block When you find the BB truck get a few more parts besides the pullies and brackets. You will need the radiator cover, fan shroud, and radiator mounting rubbers to make that four row wide core radiator fit. __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

05-03-2006, 10:49 PM	#10
f.monroe Senior Member Join Date: May 2004 Location: Caldwell,Tx. Posts: 3,648	Re: Small block to a big block You probably know this but I would check the flexplate against the torque converter before you drop the BigBlock in . I think there are two different bolt patterns on some flexplates and or some torq converters . The 454 uses an externally balanced flexplate , and the 305/350's are internally balanced ,so I am sure you will be using a different flexplate than the one currently installed and it might be worth your time to check the pattern first . Just a thought . Frank __________________ Born and proudly residing in a Red State !



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