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My father passed away a couple years ago and he left all his old car parts behind. My mother asked me to try and sell his stuff and I figured I would start with the spare engine he had sitting in his garage for about 40 years. I know it was refreshed in 2002 or so because I helped pick it up at the shop. My brother and I listed it as a LS6 454 short block on craigslist. But I received this message informing me otherwise "The engine is not an LS6. 3963512 was used starting as a 427 cu in and then became the 454 in 1970. Was used for the ls4 and ls5 as a 2 bolt main and the ls6 with 4 bolt mains. Just letting you know to possibly help you out with your sale. Good luck with it!"
So now I am super confused and lost as to what it is. The casting number is 3963512 . I can't seem to find any other way to ID it. From the little research I could gleam I think the LS6 had both 2 bolt and 4 bolt configurations? Maybe that fella was mistaken? Or am I reading that wrong? I honestly have no clue what I am talking about. My dad was the car guy and I am not.
Any help IDing and pricing it would be much appreciated. If this is in the wrong section or forum I apologize.
Some pics of said engine:
Last edited by Nemoperson; Nov 8, 2021 at 10:12 PM.
It appears to have new Speed-Pro (fka TRW) forged pistons pn L2399F.
L2399F is intended for a BBC 454 with OE 4" stroke.
there should be a raised casting date (perhaps at rear top driver side) and that may help determine block's origin.
also, there should a flat pad at front adjacent to Right passenger deck, where OE numbers/characters would be Stamped ... but sometimes are milled away during major overhaul. Those unmolested numbers can be VERY helpful in determining block's origin.
I think I see, but cannot be sure, if I see the indication crank is forged. Turn the crank, get a better angle, and look for THICK parting line which indicates a forging rather than a casting.
Crank appears to have been professionally balanced when last rebuilt.
You basically have about $2,000 worth of parts and someone might throw a few more C-Notes on the deal for machine shop work being done. If your just trying to move this out of your garage and not fund your retirement than anything north of $1,500 is money in the bank.
Agree with ebbnflow - on the opposite side of the block from the 512 casting will be a series of a letter and numbers. Example: J 22 9. The letter is the month the block was cast, in this example J means October, 22 is the 22nd day of that month and the 9 indicates the year -1969.
Due to the GM strike in 1969, the 512 block, intended for the 454, was used in Corvette production until December of 1969. When the 1970 was introduced in January of 1970 (4 months delayed), GM simply dropped the 454 crank into the 512 block.
Measure the stroke. If it is 4.00 inches, it’s a 454. If 3.76”, it’s a 427.
Look for a casting number on the crank. The 427 used a 6223 or 7115 whereas the 454’s are too many to list here.
LS6 blocks were all 100% 4 bolt main as were all SHP engines of the era. It could be a fluke thing but I doubt it......being a 2 bolt. The pistons come back as "LS6 replacement" ...but it is a late LS6 for 71.....with an opebn chamber head this piston gives a 9 to 1 compression ratio......
Pull the cam and get a number off of it too.......any and all info is useful for sale.
List it as a 454 short block with 7/16 dimple rods and a forged crank, forged pistons......should go quick. In fact, where are you as a friend may be interested.
What is your asking price?
Thank you all for your help! I really appreciate you taking your time to help me out. I am a complete layman when it comes to cars so please bear with me. My dad was a corvette guy so he knew all of this like the back of his hand.
I tried looking for the casting date and it looks illegible to my eyes. I also think I found the ID number but again looks like it was machined off. I don't have the technical know how to remove the cam unfortunately. I tried to hand crank it but it wouldn't budge.
I am located in upstate NY. Zip is 13411 if anyone is interested in taking a look
I took a bunch of pics maybe you folks can see something. Sorry for the size. If you like i can resize them.
The 7416 on the crank means it is a 454. No need to measure stroke. The pic of the cast date looks like B 4 0 which would be February 4, 1970. My guess, given it being a 2 bolt, combined with the HI-PERF PASS, would be it originally was built for an Impala, Monte Carlo, or Chevelle.
You should get a breaker bar and see if you can get it to turn. If it’s stuck, that will certainly detract from the value.
Good to know. I will give it a shot.
Thank you all for your help and your patience. I very much appreciate it.
I will repost this on craigslist and hopefully find it a new home
Is there anything stamped on this surface marked with the yellow arrow? (In the photo it would be above the cylinder on this bank, about 1/2" down from the top surface.)
There should be two stampings – one that begins with a T, the other a series of numbers. If nothing is there, it would be difficult to tell what Chevrolet model line it may have been made for. The 512 block was used both as a 427 and a 454 platform. (Corvettes certainly did come with 2-bolt mains, marked "Hi-Perf Pass" in both engine sizes.) Unless you can definitively identify that the block was intended for a performance line like Corvette, Camaro, or Chevelle, then it's just a run-of-the-mill cylinder case that could have been installed in anything from a regular passenger car or truck on up. That said, there's not any difference in the block itself for which model line it was intended for; the difference lies in the mains machining and the parts installed.
I believe you have an assembly that did not come in a production car. Your dad, or whomever he got it from, probably pulled the parts together using a common 427/454 2-bolt mains block with LS6 crankshaft and pistons. The next person would need to pull the camshaft to determine whether it is a hydraulic or solid lifter unit.
Last edited by barkingrats; Nov 9, 2021 at 10:30 PM.
I checked again and I didn't see any stampings there. The one closet to that location is that 011 number that is in the one pic I posted.
Would it be okay if I post the engine for sale in the sales thread? Not sure what the rules are for new people and whatnot.
Lacking the stamps means IDs were milled off when the block was remachined for a rebuild.
I'm not an admin, so grain of salt... I think it's fine to post it in the classifieds. Without the ID stampings there is nothing to say it didn't come in a Corvette. Your value here is in the crank and pistons. If someone really wants an LS6 configuration, they'd probably want the 4-bolt mains and put parts in another block or have this one drilled for them.
Last edited by barkingrats; Nov 10, 2021 at 09:55 AM.
OP - fyi Jebby is a long time member of the forum and a very honest, helpful person. IMO, he'll treat you very honestly if you strike an arrangement with him.
If the buyer is willing to arrange it with a shipping company sure I have no problem with that. All of the packing and lifting would need to be done from the shipping company's end though. I have no way of lifting it myself.
Is there anything stamped on this surface marked with the yellow arrow? (In the photo it would be above the cylinder on this bank, about 1/2" down from the top surface.)
There should be two stampings – one that begins with a T, the other a series of numbers. If nothing is there, it would be difficult to tell what Chevrolet model line it may have been made for. The 512 block was used both as a 427 and a 454 platform. (Corvettes certainly did come with 2-bolt mains, marked "Hi-Perf Pass" in both engine sizes.) Unless you can definitively identify that the block was intended for a performance line like Corvette, Camaro, or Chevelle, then it's just a run-of-the-mill cylinder case that could have been installed in anything from a regular passenger car or truck on up. That said, there's not any difference in the block itself for which model line it was intended for; the difference lies in the mains machining and the parts installed.
I believe you have an assembly that did not come in a production car. Your dad, or whomever he got it from, probably pulled the parts together using a common 427/454 2-bolt mains block with LS6 crankshaft and pistons. The next person would need to pull the camshaft to determine whether it is a hydraulic or solid lifter unit.
Sorry to bump this thread. I just had a potential buyer for the engine come by to take a look at it and he was able to track down the engine ID number. We had to sand some rust off of it to make it visible. I believe it is: T0225JC
Can someone please help me ID this engine
