Big block 400 in 70 GMC Sierra Grande? - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*2tons of fun* · 12-25-2009, 04:33 AM

Quote:

Originally Posted by 425HP409

In 1970 due to tightened emission laws, Chevrolet bored the 396 out .030 inches to make it a 402. There was no actual 396 in 1970 and later. They also changed to a low riser intake manifold. The same engine in a Chevelle was still called a 396 for sales. The SS396 had made a name for itself and they didn't want to mess with it by calling it a SS402.
The same cubic inch displacement engine was put in the trucks but named a 400 for some reason....

thats funny, because i just pulled a virgin 396 out of my 70.

ripdog28 · 12-25-2009, 10:45 AM

2Tons, did you measure the bore? Is it possible that it was a replacement engine which someone else put in it?

rzrback · 12-27-2009, 08:44 PM

Thx Brianthelion02 for pointing out the missing buckets....but mama likes the bench so i think i will keep it.

handyman101 · 12-29-2009, 10:35 AM

Dude, keep the bench seat!!! All I can say is, WOW!!!

**425HP409** · 12-29-2009, 01:09 PM

Quote:

Originally Posted by 2tons of fun

thats funny, because i just pulled a virgin 396 out of my 70.

I did some further research and found out through Motors Repair Manual that the 396 was still used in the trucks in 1970, whereas the cars used the 402. The 402 was used in the trucks in 1971 and 1972. The trucks used a 454 starting in 1973.
The 396 had a bore of 4.094" and stroke of 3.76". The 402 had a bore of 4.126" and stroke of 3.76" I hope this helps to eliminate the confusion.

davepl · 06-08-2014, 06:04 PM

Quote:

Originally Posted by Longhorn Man

your 70 has a 71/72 grill.

Thank goodness you said so. It's different than my 70 and I was getting scared!

davepl · 06-08-2014, 06:07 PM

Quote:

Originally Posted by brianthelion02

Bucket seats are long gone as well!LOL

Tada!

Not for sale :-)

**LockDoc** · 06-08-2014, 06:45 PM

-
2009???...ok..

**70cst** · 06-08-2014, 07:13 PM

Hey rzrback ...

to the forums and

from Ohio

on one

looking ride

**LockDoc** · 06-08-2014, 07:49 PM

Quote:

Originally Posted by 70cst

Hey rzrback ...

to the forums and

from Ohio

on one

looking ride

Actually he hasn't been on the board since 07/28/2012...

(See my earlier post)

LockDoc

12-25-2009, 10:45 AM	#27
ripdog28 Registered User Join Date: Apr 2008 Location: Imperial Beach, CA Posts: 1,040	Re: Big block 400 in 70 GMC Sierra Grande? 2Tons, did you measure the bore? Is it possible that it was a replacement engine which someone else put in it? __________________ 69 c-10 BBC 462ci, forged crank, H-beam rods, 10.5-1 KB forged pistons, Dart Iron Eagle 308cc, Straub Cam, Comp Cams chrome moly full rollers, Weiand Team G, Prosystems 950, TH400/3500 Dalenzie stall, Currie 9+ Detroit Locker w/31spline axles.3.5/6in drop. My Build. Last edited by ripdog28; 12-25-2009 at 10:47 AM.

12-27-2009, 08:44 PM	#28
rzrback Registered User Join Date: Nov 2009 Location: Rogers AR Posts: 12	Re: Big block 400 in 70 GMC Sierra Grande? Thx Brianthelion02 for pointing out the missing buckets....but mama likes the bench so i think i will keep it. Attached Images __________________ RZRBACK 1970 GMC Sierra Grande

12-29-2009, 10:35 AM	#29
handyman101 Registered User Join Date: Dec 2009 Location: Kansas City, MO Posts: 1	Re: Big block 400 in 70 GMC Sierra Grande? Dude, keep the bench seat!!! All I can say is, WOW!!!

06-08-2014, 06:45 PM	#33
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,404	Re: Big block 400 in 70 GMC Sierra Grande? - 2009???...ok.. __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

06-08-2014, 07:13 PM	#34
70cst Senior Member Join Date: Feb 2001 Location: New Madison, Ohio Posts: 21,365	Re: Big block 400 in 70 GMC Sierra Grande? Hey rzrback ... to the forums and from Ohio on one looking ride __________________ A husband can be right...or...A husband can be happy. 67-72 Chevy and GMC Trucks...The Classic Truck for the Classic Folk. 1970 CST Two tone green, 402BB, 400 Automatic, Tach, Buckets, AC, AM-FM, Tilt, GM CB, GM 8 Tract, LWB, etc JOHN 17:3...The better side of "LIFE" Remember: Everyday is a good day...Some are just gooder!



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