Big Block on VIN plate - can you tell? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**JQ-72** · 06-22-2011, 07:41 PM

Do the GVW numbers decipher whether a SWB truck had a big block or not?

JQ

**DANTIP** · 06-22-2011, 08:20 PM

In 1972, All domestic 1/2 ton Big Block trucks were required to have both heavy front and rear springs. This requirement enables us to determine if the truck was originally equipped with heavy front and rear springs by viewing the weights on the Gross Weight/VIN plate. If the truck was originally equipped with heavy front and rear springs, The "As-Manufactured" (left-hand figures) Gross Weight for this Vehicle Must be 5400 pounds, the Maximum Front End Ground Weight must be 3100 and The Maximum Rear End Weight at Ground must be either 3220 or 3500. Remember, not all trucks with these Gross Vehicle Weights were Big-Blocks, but all Big-Blocks have these Gross Weights. AGAIN, THIS IS ONLY FOR 1972 1/2 Ton Trucks!!! See examples.

I also look for original rivets on the VIN plate, frame # matching, exhaust brackets, etc.

**71blksuper4x4** · 06-22-2011, 10:22 PM

Nice Tip Dan. Trevor

sameyrasmea72 · 06-22-2011, 10:43 PM

So in 1972 at least, the vin will tell you if was a BB, but the vin will not tell you if it was a SWB?+

I SEE IT WONT TELL YOU IF IT WAS A BB, RATHER IF IT DOES NOT HAVE THOSE WEIGHTS IT WAS NOT A BB.

**too much stuff** · 06-22-2011, 10:50 PM

Some good info here!

**Dave** · 06-23-2011, 01:16 AM

The SPID will have the VIN #, wheel base and the model # info. As mentioned previously by Dan, you look at all these areas to authenticate the truck.

**DANTIP** · 06-23-2011, 11:06 AM

Here is the order I look at when determining the originality of an alleged '72 SWB BB truck.

1) VIN plate/Correct Gross Weights/Original Rivets?
2) Original SPID/Matches VIN Plate?
3) Frame Partial VIN match?
4) Frame Rail Part Numbers Correct for SWB?
5) Correctly Located/attached dual-exhaust brackets?

If any of these are not correct, I personally wouldn't be interested. Many other people don't sweat the originality details, but I will definitely pay significantly more for a correct/original SWB BB truck.

The other unique Big-Block items can be found and installed to look 100% correct and original. I feel pretty confident I could not be fooled by "put-together" truck.

**too much stuff** · 06-23-2011, 12:03 PM

Did all big block trucks have dual exhaust?

**Dave** · 06-23-2011, 12:36 PM

Every "factory" big block truck I parted out or owned had dual exhaust hangers.

68 TT · 06-23-2011, 02:49 PM

Quote:

Originally Posted by Dave

Every "factory" big block truck I parted out or owned had dual exhaust hangers.

I too have never seen a factory big block truck or car with single exhaust.

**yote1234** · 12-19-2013, 06:21 PM

anyone know if the weight ratings in 1971 big block trucks were different?

**DANTIP** · 12-19-2013, 06:30 PM

The 72 1/2 ton Big-block trucks were required to have heavy front and rear springs. The 71 and earlier were not.

Dan

**yote1234** · 12-19-2013, 06:57 PM

Quote:

Originally Posted by DANTIP

The 72 1/2 ton Big-block trucks were required to have heavy front and rear springs. The 71 and earlier were not.

Dan

ahhhh. ok thx for reply! dave

06-22-2011, 07:41 PM	#1
JQ-72 Senior Member Join Date: Feb 2001 Location: Killen, Alabama USA Posts: 3,615	Big Block on VIN plate - can you tell? Do the GVW numbers decipher whether a SWB truck had a big block or not? JQ __________________ 72 Cheyenne Super swb. Factory 402/400,tach,posi,AM/FM, A/C. Adding cruise, 8-track 72 Cheyenne Super swb. 350/350 A/C, bucket seats 72 Cheyenne swb. Factory 402/400, tilt, posi, A/C 72 Cheyenne Super K-10. 350/4 spd., posi. 72 Suburban 350/350 tilt, tach, AM/FM, A/C, luggage rack 72 GMC Sierra lwb. 350/350, A/C. medium green/olive interior

06-22-2011, 08:20 PM	#2
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,889	Re: Big Block on VIN plate - can you tell? In 1972, All domestic 1/2 ton Big Block trucks were required to have both heavy front and rear springs. This requirement enables us to determine if the truck was originally equipped with heavy front and rear springs by viewing the weights on the Gross Weight/VIN plate. If the truck was originally equipped with heavy front and rear springs, The "As-Manufactured" (left-hand figures) Gross Weight for this Vehicle Must be 5400 pounds, the Maximum Front End Ground Weight must be 3100 and The Maximum Rear End Weight at Ground must be either 3220 or 3500. Remember, not all trucks with these Gross Vehicle Weights were Big-Blocks, but all Big-Blocks have these Gross Weights. AGAIN, THIS IS ONLY FOR 1972 1/2 Ton Trucks!!! See examples. I also look for original rivets on the VIN plate, frame # matching, exhaust brackets, etc. Attached Images Last edited by DANTIP; 06-22-2011 at 08:30 PM.

06-22-2011, 10:22 PM	#3
71blksuper4x4 SWB 4x4 Collector Join Date: Jun 2001 Location: Osage City, KS Posts: 5,155	Re: Big Block on VIN plate - can you tell? Nice Tip Dan. Trevor __________________ TREVOR 1970 CST swb 4x4 (speedwarning,cruise,tilt,tach,8track, original red shoulder belts,tow hooks) 1972 Jimmy (soon to be Hickey cloned) 1971 Cheyenne Super 4x4 swb (tilt,tach,buckets, original blue shoulder belts,am/fm,cruise,tow hooks, dealer 8 track) 1972 Cheyenne Super K20 4x4 Custom Camper (tilt, tach, am/fm, tow hooks, bed toolbox, aux gas tank 1972 Cheyenne Super Crew Cab K30 4x4 Duramax, Allison, np205, buckets, tow hooks (CURRENT PROJECT) http://67-72chevytrucks.com/vboard/s...d.php?t=624819 1989 V3500 Crew Cab (454tbi, NV4500, np205) 1970 Chevelle SS (LS5 454,th400,8track,buckets,tach) :2004 Jeep Wrangler Rubicon (daily driver) WTB: 1968-70 Cruise Control Lever

06-22-2011, 10:43 PM	#4
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	Re: Big Block on VIN plate - can you tell? So in 1972 at least, the vin will tell you if was a BB, but the vin will not tell you if it was a SWB?+ I SEE IT WONT TELL YOU IF IT WAS A BB, RATHER IF IT DOES NOT HAVE THOSE WEIGHTS IT WAS NOT A BB. __________________ 72 Cheyenne Super 80 Silverado Blazer 2wd Last edited by sameyrasmea72; 06-22-2011 at 10:47 PM.

06-22-2011, 10:50 PM	#5
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,769	Re: Big Block on VIN plate - can you tell? Some good info here! __________________ 67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

06-23-2011, 01:16 AM	#6
Dave DND Trucks Join Date: Dec 1999 Location: NW Indiana Posts: 2,396	Re: Big Block on VIN plate - can you tell? The SPID will have the VIN #, wheel base and the model # info. As mentioned previously by Dan, you look at all these areas to authenticate the truck.

06-23-2011, 11:06 AM	#7
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,889	Re: Big Block on VIN plate - can you tell? Here is the order I look at when determining the originality of an alleged '72 SWB BB truck. 1) VIN plate/Correct Gross Weights/Original Rivets? 2) Original SPID/Matches VIN Plate? 3) Frame Partial VIN match? 4) Frame Rail Part Numbers Correct for SWB? 5) Correctly Located/attached dual-exhaust brackets? If any of these are not correct, I personally wouldn't be interested. Many other people don't sweat the originality details, but I will definitely pay significantly more for a correct/original SWB BB truck. The other unique Big-Block items can be found and installed to look 100% correct and original. I feel pretty confident I could not be fooled by "put-together" truck.

06-23-2011, 12:03 PM	#8
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 13,769	Re: Big Block on VIN plate - can you tell? Did all big block trucks have dual exhaust? __________________ 67 gmc custom lwb dakota truck. Sold...And bought back 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

06-23-2011, 12:36 PM	#9
Dave DND Trucks Join Date: Dec 1999 Location: NW Indiana Posts: 2,396	Re: Big Block on VIN plate - can you tell? Every "factory" big block truck I parted out or owned had dual exhaust hangers.

12-19-2013, 06:21 PM	#11
yote1234 Senior Member Join Date: Feb 2003 Location: Gold Canyon Arizona Posts: 4,383	Re: Big Block on VIN plate - can you tell? anyone know if the weight ratings in 1971 big block trucks were different? __________________ 1971 K5 CST Blazer 1951 -3100 5 window short bed 4sp 1965 Chevelle Malibu 283 (sadly sold) 1968 Camaro 327 1968 Honda mini-trail z50a #377 1966 uh 1-D Huey

12-19-2013, 06:30 PM	#12
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,889	Re: Big Block on VIN plate - can you tell? The 72 1/2 ton Big-block trucks were required to have heavy front and rear springs. The 71 and earlier were not. Dan



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