1970 454
I am traveling and away from my judging manuals. Did the 1970 454 come with a smog pump / A.I.R. system similar to the 1969?
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In Appreciation of John Hinckley -
Re: 1970 454
Ken-----
I have heard that some 1970-71 LS-5 had manifolds with the AIR fittings and internal square drive plugs in them. Of course, I cannot confirm if these were originals, or not. However, the fact that those thought to be originals all seem to have the internal square drive plugs gives some credence to the notion that they are original for the reason that the plugs "match" and because internal square drive plugs are not that common.In Appreciation of John HinckleyComment
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Re: 1970 454
We mentioned this and the serial number range they have been seen in the 1970-1972 TIM&JG. I am pretty sure it has been there since the 1993 version of the manual. That might be where you "heard" of it Joe.TerryComment
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Re: 1970 454
JOE
My 454 is a March car & has the square drive plugs. I beleave that they were original to that engine. I can't rememer what the cast dates were but the preceded the engine build date.
The Corvette was a one owner with original paint ETC & low miles.
Corvette was bought new at McDorman Chev. Canal Winchester Oh. It was sort of the Viat Nam story except he buoght it after he got back & had to sell it after two divorces. He was really bitter about selling it when I bought it 15 years ago.
KEN
PS I stand corrected. i went out to look at the plugs & they rere the recessed ones. My dip stick is the long one but the button on the handle is mia.Last edited by Kenneth B.; October 23, 2010, 10:03 AM.65 350 TI CONV 67 J56 435 CONV,67,390/AIR CONV,70 454/air CONV,
What A MAN WON'T SPEND TO GIVE HIS ASS A RIDEComment
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Re: 1970 454
Little off the original subject; but was the 71 LS-6 engine offered in
the Chevelle or just the Corvette?
LarryLarry
LT1 in a 1LE -- One of 134Comment
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Re: 1970 454
Larry------
The LS-6 was available in the Chevelle for 1970, but not for 1971.
The LS-6 was available in Corvette for 1971 but not for 1970.
The Chevelle version of the LS-6 had 11:1 compression and cast iron heads. It was rated at 450 hp. The Corvette version had 9.0:1 compression and aluminum heads and was rated at 425 hp.
The Chevelle version used log type exhaust manifolds whereas the Corvette version used the "header" type cast iron manifolds.
The Chevelle version used a Chevelle-type oil pan whereas the Corvette version used the Corvette-specific oil pan.
The Chevelle version used a long-leg style waterpump whereas the Corvette version used the short leg waterpump.
So, while both engines were identified as LS-6, there were certainly a lot of differences between them.In Appreciation of John HinckleyComment
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Re: 1970 454
Here are some photos of my passenger side LS5 manifold plugs. Driver's side has no plugs/ holes at all. Motor was built 12/19/69.1969 Riverside Gold Coupe, L71, 14,000 miles. Top Flight, 2 Star Bowtie.Comment
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Re: 1970 454
Chris------
Yes, these are the plugs that have been previously described as being used in apparently original 1970 big block applications.
I think I know why your passenger side manifold has the plugs and the driver side does not. For 1970, the driver side big block manifold changed to a new design. This manifold was GM casting #3969869. Without AIR fittings it was known as GM PART #3969869. With AIR fittings it was known as GM PART #3969923. For 1970, there would have been very little use of the 3969923. In fact, the only application would have been the still-born LS-7. So, the vast majority of the manifolds produced would likely have been the GM PART #3969869 and that's what was used on your car. Nevertheless, some of the GM PART #3969923 manifolds were likely produced, too. Those would either have had to end up on 1970 LS-5 PRODUCTION engines (with plugs) or be sent to GMSPO for SERVICE.
The right side manifold was another story. For 1970, it was a carry-over from the 1966-69 period. This manifold was GM CASTING #3880828 and, without AIR fittings was also known as GM PART #3880828. With AIR fittings it was known as GM PART #3880834. However, the last use of this manifold without AIR fittings before 1970 was for 1967 Corvette big blocks without K-19. So, there were probably lots of these GM PART #3880834 manifolds produced for the 68-69 period and, so, these were used on 1970 models (with plugs)until the supply was diminished to some point.
I fully expect, though, that folks with 1970 Corvettes with LS-5 and having original plugged left side manifolds have manifolds that were originally intended for the LS-7. That would have been the only 1970 application that would have required the 3969923 manifold.In Appreciation of John HinckleyComment
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Re: 1970 454
Thanks Joe for solving that mystery. I always wondered why the difference in the two manifold designs. Chris1969 Riverside Gold Coupe, L71, 14,000 miles. Top Flight, 2 Star Bowtie.Comment
I think with the AIR pump.
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