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Discussion Starter · #1 ·
Hello all,

I just happened upon a complete LS6 motor. It's a 3963512 4 bolt block dated C470 with 3964291 heads, both dated A2070. The block is a standard bore and needs no overbore at all. I have the low rise aluminum intake (3963569) , 7416 crank (.010 under and looks good), dimple rods, and 3963550 pistons. It also has a GM 4366 camshaft (which to my understanding is not original). What is this thing worth??? I've been looking around for complete ls6's for sale, and I haven't found many to compare it against. Any help would be appreciated!
 

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I think this would be considered a later 512 block as opposed to early. I've seen a lot of 512's that were cast in 69 in anticipation of the ls-6 coming out in Dec of 69. I'm not completely sure about the head casting date but I think they should be later than the block. Maybe someone else will have a more definative answer for you.
 

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I think this would be considered a later 512 block as opposed to early. I've seen a lot of 512's that were cast in 69 in anticipation of the ls-6 coming out in Dec of 69. I'm not completely sure about the head casting date but I think they should be later than the block. Maybe someone else will have a more definative answer for you.
No reason the heads have to be cast after the casting date of the block. The only thing that would be important is that they be cast before assembly date of the engine. Sometimes they are close, sometimes they are not. But since no assembly date exists here because of the deck resurface, you cannot know if they were the heads to this motor. They must also be peanut plug (5/8" tapered seat) spark plugs, as #291 castings can also be found as large plug (washer type). Those would be service replacement heads for 69 and earlier applications. Regardless, this is a valuable engine. Especially if you have a LS6 car to put it in. The lack of assembly code will hurt its value to some people. Also of high value would be any other special parts, like carb, dist, exhaust manifolds, etc, as most of this stuff was removed and thrown out in search of more speed. If all of that stuff is there, it can as much as double the price!!!

Jeff Dotterer
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Diamond Restored Judge
 

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I think this would be considered a later 512 block as opposed to early. I've seen a lot of 512's that were cast in 69 in anticipation of the ls-6 coming out in Dec of 69. I'm not completely sure about the head casting date but I think they should be later than the block. Maybe someone else will have a more definative answer for you.
My block casting is I-9-9,heads J 31 9/K 3 9 pad T11 29 CRR /12B BAL Built.Carb,alt,dist are all early sept.
 

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Discussion Starter · #9 ·
Not sure why that would be strange...it does have other machine work like the crank being ground. The cylinders were honed as I can see the cross hatch from the honing. It looks like the motor just sat for a very long time and somebody just pulled it apart and freshened it up. It did have new rings and bearings. So nobody has a number value?
 

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They must also be peanut plug (5/8" tapered seat) spark plugs, as #291 castings can also be found as large plug (washer type).
Jeff Dotterer
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Were some of the #291 castings machined to fit both the 5/8" tapered seat spark plugs, and the large washer type plug ?

I had a set of used 291s that came with 5/8" tapered seat plugs but saw the machined counter bore for the washer type plug.
At first, I thought some hacker put in the wrong plug but looking closer it looked like either plug would work. I ran them with washer type with no problems.
 

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"My block casting is I-9-9,heads J 31 9/K 3 9 pad T11 29 CRR /12B BAL Built.Carb,alt,dist are all early sept"..........There werent any Ls6 distributors made in early september 69,or september 69 at all..
You're right, there weren't any Sept. 69 LS6 distributors. :) There were some made in early Nov. 69, and that would work for his T1129CRR / 12B engine, as that is Nov. 29, 1969.:yes:
 

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Imo, if you have an LS6 car to put it in and it is an LS6 motor regardless of the dates it is a great find. if the vin pad is gone from decking the only reason to have date coded parts is revenue. but the worth is based on the fact that it is an LS6 CAR WITH AN LS6 MOTOR. if i had a 70 and could not document it as an LS6 i probably would not pay alot for an LS6 MOTOR. probably cuz i am poor.:yes: well according to my tax lady i am poor.
 
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