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

**Already Gone** · 11-21-2011, 12:51 PM

Did the 70 big block trucks come with the 396 or 402? I thought 67/70 were 396's and 71/72 were 402's?

sameyrasmea72 · 11-21-2011, 01:02 PM

I think a 70 was a 402 also. Just the 68's and 69's were 396's. Not 100% positive.

**RenoKeene** · 11-21-2011, 01:11 PM

In 70 they went to a 402 but listed them as 396 or 400. My big block 70 GMC has the original engine and it is a 402.
You can find lots of threads in here about this but the bottom line is that nobody really knows why they didn't badge them as 402's or list them on the SPID as such.
I'm glad I have one...

**Already Gone** · 11-21-2011, 01:34 PM

Thanks for the ionfo. I'm looking at buying a 70 and the owner is advertising it as a 402 and I wanted to clarify as I don't want a transplanted engine .

**DANTIP** · 11-21-2011, 01:42 PM

If the engine is original it should be a 402 with a stamp on the block in front of the passenger side cylinder head like T****TBG (TH-400), or T****TBH (Manual Trans). The stars are for the assembly date. Good Luck!!

**RenoKeene** · 11-21-2011, 01:54 PM

My stock intake casting number is 3955287, 70-71 402. You should be able to see this pretty easily.

If you can get the block casting number off of the top back driver side of the block you can go to this link and decode it...
http://www.nastyz28.com/bbcmenu.php

The 402 is a good engine...there is a lot you can do with it.

Good Luck.

webfoot · 11-21-2011, 02:04 PM

I suppose it has something to do with branding. Since the 1st big block SS chevelles came out it had been "SS396" they had marketed and turned into a brand. Probably not worth it to GM for all the explanation for 6 cubic inches when it is essentially the same powerplant.

However if you got a big block malibu it was called a malibu 400, probably to separate it from the SS brand.

**too much stuff** · 11-21-2011, 02:30 PM

Quote:

Originally Posted by sameyrasmea72

I think a 70 was a 402 also. Just the 68's and 69's were 396's. Not 100% positive.

I think this is correct.

**leddzepp** · 11-21-2011, 04:51 PM

Quote:

Originally Posted by Already Gone

Thanks for the ionfo. I'm looking at buying a 70 and the owner is advertising it as a 402 and I wanted to clarify as I don't want a transplanted engine .

the only way to verify the engine is original to the truck is if you have the buildsheet.
Posted via Mobile Device

sameyrasmea72 · 11-21-2011, 04:52 PM

Quote:

Originally Posted by leddzepp

the only way to verify the engine is original to the truck is if you have the buildsheet.
Posted via Mobile Device

Or the protec-to-plate.

**leddzepp** · 11-21-2011, 05:16 PM

Quote:

Originally Posted by sameyrasmea72

Or the protec-to-plate.

...or the protecto plate, lol
Posted via Mobile Device

11-21-2011, 12:51 PM	#1
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,109	Big Block Question Did the 70 big block trucks come with the 396 or 402? I thought 67/70 were 396's and 71/72 were 402's? __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

11-21-2011, 01:02 PM	#2
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	Re: Big Block Question I think a 70 was a 402 also. Just the 68's and 69's were 396's. Not 100% positive. __________________ 72 Cheyenne Super 80 Silverado Blazer 2wd

11-21-2011, 01:11 PM	#3
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,022	Re: Big Block Question In 70 they went to a 402 but listed them as 396 or 400. My big block 70 GMC has the original engine and it is a 402. You can find lots of threads in here about this but the bottom line is that nobody really knows why they didn't badge them as 402's or list them on the SPID as such. I'm glad I have one... Attached Images __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

11-21-2011, 01:34 PM	#4
Already Gone 70+ ( Old Skool Club ) Join Date: Nov 2003 Location: Saskatoon, Saskatchewan ,Canada Posts: 9,109	Re: Big Block Question Thanks for the ionfo. I'm looking at buying a 70 and the owner is advertising it as a 402 and I wanted to clarify as I don't want a transplanted engine . __________________ 1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021

11-21-2011, 01:42 PM	#5
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,882	Re: Big Block Question If the engine is original it should be a 402 with a stamp on the block in front of the passenger side cylinder head like T**TBG (TH-400), or T**TBH (Manual Trans). The stars are for the assembly date. Good Luck!!

11-21-2011, 01:54 PM	#6
RenoKeene Florida Edition Join Date: Oct 2010 Location: Fruitland Park, FL Posts: 4,022	Re: Big Block Question My stock intake casting number is 3955287, 70-71 402. You should be able to see this pretty easily. If you can get the block casting number off of the top back driver side of the block you can go to this link and decode it... http://www.nastyz28.com/bbcmenu.php The 402 is a good engine...there is a lot you can do with it. Good Luck. __________________ 70 GMC Short Stepside "Rose"-An American Beauty: Factory 402/TH400, AM/FM, AC, Tilt, Tach, Buckets, Posi, PS, PB, 3-5 Drop, Complete Resto-Rod 67 C-20 Slant Back Wrecker "Mad Max" 67 C-10 Ratrod "Step-N-Wolf" 71 Serro Scotty Sportsman camper "Scotty" 97 LT1 Z28 "The Hornet" Link to more pics of "Rose" http://67-72chevytrucks.com/vboard/a...p?albumid=1684 Check out my "Cheap Tricks" thread and add to it if you can, lots of good info there. http://67-72chevytrucks.com/vboard/s...d.php?t=489394

11-21-2011, 02:04 PM	#7
webfoot Registered User Join Date: Nov 2007 Location: Hermiston, OR Posts: 947	Re: Big Block Question I suppose it has something to do with branding. Since the 1st big block SS chevelles came out it had been "SS396" they had marketed and turned into a brand. Probably not worth it to GM for all the explanation for 6 cubic inches when it is essentially the same powerplant. However if you got a big block malibu it was called a malibu 400, probably to separate it from the SS brand. __________________ *Running in place gets you nowhere fast.* -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC.



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