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Old 12-25-2009, 04:33 AM   #26
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Re: Big block 400 in 70 GMC Sierra Grande?
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Originally Posted by 425HP409 View Post
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.
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Old 12-25-2009, 10:45 AM   #27
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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?
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Old 12-27-2009, 08:44 PM   #28
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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.
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Old 12-29-2009, 10:35 AM   #29
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Re: Big block 400 in 70 GMC Sierra Grande?
Dude, keep the bench seat!!! All I can say is, WOW!!!
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Old 12-29-2009, 01:09 PM   #30
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Re: Big block 400 in 70 GMC Sierra Grande?
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Originally Posted by 2tons of fun View Post
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.
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Old 06-08-2014, 06:04 PM   #31
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Re: Big block 400 in 70 GMC Sierra Grande?
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your 70 has a 71/72 grill.
Thank goodness you said so. It's different than my 70 and I was getting scared!
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Old 06-08-2014, 06:07 PM   #32
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Re: Big block 400 in 70 GMC Sierra Grande?
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Bucket seats are long gone as well!LOL
Tada!

Not for sale :-)
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Old 06-08-2014, 06:45 PM   #33
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Re: Big block 400 in 70 GMC Sierra Grande?
-
2009???...ok..
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Old 06-08-2014, 07:13 PM   #34
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Re: Big block 400 in 70 GMC Sierra Grande?
Hey rzrback ...

to the forums and from Ohio

on one looking ride
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Old 06-08-2014, 07:49 PM   #35
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Re: Big block 400 in 70 GMC Sierra Grande?
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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)

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