1970 396 Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72Bob · 05-07-2005, 07:04 PM

I just got a 1970 Big Block 3/4 ton truck, What I have read, it should be a 402, but the glove blox says 396 option code L47.
Is the 396 correct?, or should it be a 402? and what is the HP ratting?

Since the body is rusty, we thinking about putting it in a 68 Camaro body.

Longhorn Man · 05-07-2005, 07:18 PM

In the trucks, GM made things real confusing.
The engine ios a 402.
The option is for a 396.
The fender badge says 400.

The 396 and 402 are closer related than the other big blocks, the 402 is nothing more than a 30 over 396. There's many storys as to why, and they range from fire/flood damaged blocks to improperly bored blocks that ended up getting rebored, and inner office politics...just to name a few. Personally, i buy into the politics one.... GM couldn't have a small block being bigger than a big block, and in 70, the 400 small block was born. So they gave the 396 a quick shave and a hair cut and were pleased. However, in the high perfomance circles, the 396 had quite a following, and becouse of this, there were many 402 engines badged as 396 in the cars.
Confusing huh?

72Bob · 05-07-2005, 07:32 PM

Great info.

I will check the bore when the motor is pulled.

Thanks, 72BOB

05-07-2005, 07:04 PM	#1
72Bob Registered User Join Date: Sep 2002 Location: Burlington, WA Posts: 298	1970 396 Question I just got a 1970 Big Block 3/4 ton truck, What I have read, it should be a 402, but the glove blox says 396 option code L47. Is the 396 correct?, or should it be a 402? and what is the HP ratting? Since the body is rusty, we thinking about putting it in a 68 Camaro body. __________________ 1971 GMC Sierra 3/4 Ton 4x4 1972 Chevrolet SWB 4x4 RIP LeRoy

05-07-2005, 07:32 PM	#3
72Bob Registered User Join Date: Sep 2002 Location: Burlington, WA Posts: 298	Great info. I will check the bore when the motor is pulled. Thanks, 72BOB __________________ 1971 GMC Sierra 3/4 Ton 4x4 1972 Chevrolet SWB 4x4 RIP LeRoy

05-07-2005, 07:18 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	In the trucks, GM made things real confusing. The engine ios a 402. The option is for a 396. The fender badge says 400. The 396 and 402 are closer related than the other big blocks, the 402 is nothing more than a 30 over 396. There's many storys as to why, and they range from fire/flood damaged blocks to improperly bored blocks that ended up getting rebored, and inner office politics...just to name a few. Personally, i buy into the politics one.... GM couldn't have a small block being bigger than a big block, and in 70, the 400 small block was born. So they gave the 396 a quick shave and a hair cut and were pleased. However, in the high perfomance circles, the 396 had quite a following, and becouse of this, there were many 402 engines badged as 396 in the cars. Confusing huh?



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