Machining off block numbers
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
if there is a echo in here DO NOT have the pad decked. the only real reason to deck the block is one to remove anther set of numbers to FRAUD someone, or because the engine over heated and warped. any other time its the shop trying to sell you something to justify them having the equipment needed
Race Director
Joined: Mar 2003
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From: Eustis ( Area 51 Bat Cave ) Fl
Numbers matching doesnt matter?
That simply is not true, im a modder, but i know that for some people on some cars the born with engine with its orginal stamp and marks is paramount, and anything else is akin to some bastard stepchild, hurting value and limiting buyers, these cars are in many cases 68 to 72s and very nice/orginal.
I also know as reflected on this forum there are just as many or more buyers of c3s especially 74 to 82s who are buying these cars to restomod and do not care at all about "numbers". Keeping the old engine for possible resell time means zero to them.
So where are you?
If you have a born with engine numbers matching orginal car and are into that seems a shame even if you are a modder and dont care about numbers to just discard that engine or have its numbers milled off,
If decking is a must and If a machinist who can work around the numbers isnt an option, perhaps the better bet is save that old engine and install a crate engine,
That simply is not true, im a modder, but i know that for some people on some cars the born with engine with its orginal stamp and marks is paramount, and anything else is akin to some bastard stepchild, hurting value and limiting buyers, these cars are in many cases 68 to 72s and very nice/orginal.
I also know as reflected on this forum there are just as many or more buyers of c3s especially 74 to 82s who are buying these cars to restomod and do not care at all about "numbers". Keeping the old engine for possible resell time means zero to them.
So where are you?
If you have a born with engine numbers matching orginal car and are into that seems a shame even if you are a modder and dont care about numbers to just discard that engine or have its numbers milled off,
If decking is a must and If a machinist who can work around the numbers isnt an option, perhaps the better bet is save that old engine and install a crate engine,
Race Director
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From: Snake handler
Last edited by TJefferson2020; Sep 14, 2018 at 06:06 PM.
Race Director
Joined: Mar 2003
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From: Eustis ( Area 51 Bat Cave ) Fl
this happened to me with my rare 1970 LT1. Destroyed the value of the motor. I believe only 1450 were made. NEVER assume the machinist will leave the stamping. I took mine to a well known Chevy shop in Milwaukee amd never imagined a Chevy specialty shop would have to be told to save the casting number on such a rare engine.
Melting Slicks
Joined: Jul 2006
Posts: 3,100
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From: Massapequa Park NY
Decking the block can create more problems than people realize. Someone above said it helps make all the surfaces true. Well, this is not true at all. When you deck the block, other parts also have to be shaved such as the intake manifold. Think about it. The block is a V. If you cut off the tops of the V then it gets shorter and the intake manifold will not sit correctly on top of the motor. The heads will be lower and not line up to the manifold properly. That creates all sorts of problems.
One of the best Chevy engine builders on Long Island who has been in business for longer than anyone can remember and who also does building for Kevin Mackay very rarely ever has to deck a block because most never need it. The only time its needed is if its warped or uneven due to some form of bad damage.
Now with a decked block if you decide to change a intake manifold in the future, it will not function at top efficiency unless you have it machined to fit a decked block. Things will not line up properly. It may not even bolt down properly. That creates vacuum leaks.
Decking is bad unless its absolutely necessary which is unusual. If the reason he gave you was because it was rebuilt before, then its even more BS.
Is your block damaged due to overheating or something like that? Are you blowing head gaskets? If so, then maybe you need it. If not, well.....
I would call another machinist.
One of the best Chevy engine builders on Long Island who has been in business for longer than anyone can remember and who also does building for Kevin Mackay very rarely ever has to deck a block because most never need it. The only time its needed is if its warped or uneven due to some form of bad damage.
Now with a decked block if you decide to change a intake manifold in the future, it will not function at top efficiency unless you have it machined to fit a decked block. Things will not line up properly. It may not even bolt down properly. That creates vacuum leaks.
Decking is bad unless its absolutely necessary which is unusual. If the reason he gave you was because it was rebuilt before, then its even more BS.
Is your block damaged due to overheating or something like that? Are you blowing head gaskets? If so, then maybe you need it. If not, well.....
I would call another machinist.
Safety Car
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From: Orlando FL
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Take a picture to verify then stamp it. EVeryone scoffs at restamp but seriously if the ORIGINAL block is that important and you can prove it then who cares about the restamping? There was a member here who recently posted about his rebuild. He took pics (maybe even vid) of his original #s, documented the build and all he got was "You devalued the car". BS. Not rocking the boat, just an opinion. Would you really walk away from a car that tripped your trigger, say some guy proved to you it was original, decent restamp but it wasnt a GM stamp? Come on...
QMP racing in Chatsworth Ca has a CNC program just for guys who want a blueprinted engine but want to save the #s, sure other shops do. not sure how one could do it wiht he usual equiptment, I believe that grinding wheel has to make a complete pass over the deck. Cant stop then go back...if one did he is one talented ****. Maybe GOFAST can pipe in.
The only 2 cars Ive owned out of over 50 where the buyer seemed to think it meant something was a 69 rs ss, 70 SS 454 Camino and a 70 Z28. The Camino guy even reused the original pistons (thats a rebuild?)Everyone knows stuff wears out, breaks as these cars are old period. Just another viewpoint not saying ones right nor wrong. To me most times its part of a sales pitch to the noob who seems to believe thats the only way a cars worth anything.
QMP racing in Chatsworth Ca has a CNC program just for guys who want a blueprinted engine but want to save the #s, sure other shops do. not sure how one could do it wiht he usual equiptment, I believe that grinding wheel has to make a complete pass over the deck. Cant stop then go back...if one did he is one talented ****. Maybe GOFAST can pipe in.
The only 2 cars Ive owned out of over 50 where the buyer seemed to think it meant something was a 69 rs ss, 70 SS 454 Camino and a 70 Z28. The Camino guy even reused the original pistons (thats a rebuild?)Everyone knows stuff wears out, breaks as these cars are old period. Just another viewpoint not saying ones right nor wrong. To me most times its part of a sales pitch to the noob who seems to believe thats the only way a cars worth anything.
Last edited by cv67; Sep 15, 2018 at 07:42 AM.
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Race Director
Joined: Jul 2015
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From: SW Florida.
use composite head gaskets and the block deck will seal just fine. if you want better compression height, they sell pistons .010 to .020 higher to zero-deck without machining the block.
Le Mans Master
Joined: May 2006
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From: League City Tx
Definitely do NOT deck the block if he is going to lose the stamps. Find another machinist, or just don't deck the block. If its a stock type rebuild, it will be fine without decking the block, assuming there is no current issues...(blown/leaking head gaskets etc etc).
No big deal on the aluminum heads, just save the originals and send them with the car if you sell it, value is still the same. However you lose that engine stamp, you lose HUGE on the value of the car.
Do NOT restamp the block.. Even though they can match the stamps pretty well, they can NOT match the original broach marks on the pad itself. I have a restamped 396 block and ANYONE can tell its not original, even though the stamps are a good reproduction, its very obvious the pad has been decked.
No big deal on the aluminum heads, just save the originals and send them with the car if you sell it, value is still the same. However you lose that engine stamp, you lose HUGE on the value of the car.
Do NOT restamp the block.. Even though they can match the stamps pretty well, they can NOT match the original broach marks on the pad itself. I have a restamped 396 block and ANYONE can tell its not original, even though the stamps are a good reproduction, its very obvious the pad has been decked.
Last edited by ajrothm; Sep 15, 2018 at 09:17 AM.
Melting Slicks
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Le Mans Master
Joined: May 2003
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From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Take a picture to verify then stamp it. EVeryone scoffs at restamp but seriously if the ORIGINAL block is that important and you can prove it then who cares about the restamping? There was a member here who recently posted about his rebuild. He took pics (maybe even vid) of his original #s, documented the build and all he got was "You devalued the car". BS. Not rocking the boat, just an opinion. Would you really walk away from a car that tripped your trigger, say some guy proved to you it was original, decent restamp but it wasnt a GM stamp? Come on....
Hmmmm...Now how do I know that "the picture" wasn't photoshopped?
I took a picture of a hundred dollar bill before I put it in my wallet...somehow now it's gone......I decided to just make another one- used the same serial number- It's all good!!!
I'm not a number matching guy...but restamping no matter what -I feel ( and law enforcement) is fraud....
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
Moved here 21 years ago, met up with many in the Corvette community, one guy in particular had a set of stamps that were IDENTICAL to what the factory used....and so would finish a block just right, and restamp it......passed many a car off in Bloomington Gold, I asked other guys if that was true....individually....not in a group....and sure enough, they all said it was true.....
so hoo am I to argue??
so hoo am I to argue??
Team Owner
Joined: Feb 2003
Posts: 54,059
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Moved here 21 years ago, met up with many in the Corvette community, one guy in particular had a set of stamps that were IDENTICAL to what the factory used....and so would finish a block just right, and restamp it......passed many a car off in Bloomington Gold, I asked other guys if that was true....individually....not in a group....and sure enough, they all said it was true.....
so hoo am I to argue??
so hoo am I to argue??
Pro
Joined: Nov 2007
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From: hernando fl
i find it hard to believe stamps were changed every day ,if that is the case there are probably hundreds of sets of stamps that found their way out of the building and in to lots of assembly line workers garages. gm was not known for throwing money around replacing perfectly good tools just because it was a new day . i would have to assume the stamps were pretty well worn out before they were changed.
Team Owner
Joined: Feb 2003
Posts: 54,059
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
Flint was building 5,000 engines a DAY they could ware some things out
http://www.camaros.org/pdf/flint_engine.pdf
http://www.camaros.org/pdf/flint_engine.pdf
Le Mans Master
Joined: Mar 2004
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From: Little Rock AR
i find it hard to believe stamps were changed every day ,if that is the case there are probably hundreds of sets of stamps that found their way out of the building and in to lots of assembly line workers garages. gm was not known for throwing money around replacing perfectly good tools just because it was a new day . i would have to assume the stamps were pretty well worn out before they were changed.
Safety Car
Joined: Feb 2012
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From: Orlando FL
In younger days, I worked at the GM Hydra-Matic (transmission) plant at the Willow Run Airport for a few years. I don`t ever recall an "end of day". It ran 24/7 and you either worked day shift, afternoon shift, or night shift. Production numbers for "per day" units meant produced over all 3 shifts in a 24 hour period. I ram a milling machine, making output shafts. Tools like saw blades, drill bits, stamps, etc. were ONLY replaced when they were broken or COMPLETELY worn out and would not work anymore. I can not speak to how any other plants operated, but I find it hard to believe that any other plant was run much different.
Le Mans Master
Joined: Mar 2004
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From: Little Rock AR
In younger days, I worked at the GM Hydra-Matic (transmission) plant at the Willow Run Airport for a few years. I don`t ever recall an "end of day". It ran 24/7 and you either worked day shift, afternoon shift, or night shift. Production numbers for "per day" units meant produced over all 3 shifts in a 24 hour period. I ram a milling machine, making output shafts. Tools like saw blades, drill bits, stamps, etc. were ONLY replaced when they were broken or COMPLETELY worn out and would not work anymore. I can not speak to how any other plants operated, but I find it hard to believe that any other plant was run much different.
" to be reused on another day.