427 numbers question
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Intermediate
Joined: Jan 2007
Posts: 49
Likes: 0
427 numbers question
hi all
just purchased a 1968 vette and am checking all parts for number matching status. Everything that I have vhecked so far matches the braodcast sheet (intake, carbs, heads, block, front deck does not appear to be a restamp, exhaust manifolds); there are some markings next to the oil pressure line fitting on the bottom of the block with the cast notes as follows:
hi perf
k pass
20
this is an L71 427..... just curious
thanks!
just purchased a 1968 vette and am checking all parts for number matching status. Everything that I have vhecked so far matches the braodcast sheet (intake, carbs, heads, block, front deck does not appear to be a restamp, exhaust manifolds); there are some markings next to the oil pressure line fitting on the bottom of the block with the cast notes as follows:
hi perf
k pass
20
this is an L71 427..... just curious
thanks!
Le Mans Master
Joined: Nov 2001
Posts: 8,831
Likes: 1,959
From: LONG ISLAND
2025 C3 ('68-'73) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
hi all
just purchased a 1968 vette and am checking all parts for number matching status. Everything that I have vhecked so far matches the braodcast sheet (intake, carbs, heads, block, front deck does not appear to be a restamp, exhaust manifolds); there are some markings next to the oil pressure line fitting on the bottom of the block with the cast notes as follows:
hi perf
k pass
20
this is an L71 427..... just curious
thanks!
just purchased a 1968 vette and am checking all parts for number matching status. Everything that I have vhecked so far matches the braodcast sheet (intake, carbs, heads, block, front deck does not appear to be a restamp, exhaust manifolds); there are some markings next to the oil pressure line fitting on the bottom of the block with the cast notes as follows:
hi perf
k pass
20
this is an L71 427..... just curious
thanks!
What is it you want to know ? post a pic if you can of the engine pad........maybe i can help.......post whatever numbers you have........!!!
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Pad numbers will be TXXXXIR or IU and 18S4xxxxx
T for Tonawanda Engine Assembly Plant
XXXX for calendar date engine was assembled; will predate vehicle assembly date on trim tag.
IR for 427/435; IU for same engine with L89 option
1 for Chevrolet Corvette
8 for 1968
S for St. Louis Assembly plant
4xxxxx for vehicle consecutive unit number; should match VIN.
T for Tonawanda Engine Assembly Plant
XXXX for calendar date engine was assembled; will predate vehicle assembly date on trim tag.
IR for 427/435; IU for same engine with L89 option
1 for Chevrolet Corvette
8 for 1968
S for St. Louis Assembly plant
4xxxxx for vehicle consecutive unit number; should match VIN.
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
hi perf
k pass
20
This numbers don't mean a lot, except that this is a hi performabce passenger car block.
What you need to check is the block casting number , found on top aft end near to the bellhousing.
For 68 early cars , it is 3916321 , for late cars as of about February 68, it is 3935439. Also the block casted date is interesting, found on the pax side just above the oil pan about mid of the block. It is upside down and should read something like H 13 7 ( H for month , 13 is day, 7 for 1967 ) this being an example for a early 68. Casted date should be around 3 month b4 the car's build date, found on the drivers side door pillar.
The blocks stamp pad numbers read the suffix, explained already in previous thread and the car's VIN ( last 18S + 5 digit car VIN number )
If all this gives, the engine is most probably numbers matching.
For the heads, you need to remove the valve covers to get to the casted date and numbers.
The tri-power intake casted date is under the oil splash shield underneath the intake, not visible.
Nothing beats a 427 CI solid lifter square port engine setup.
Good luck. Günther
hi perf
k pass
20
This numbers don't mean a lot, except that this is a hi performabce passenger car block.
What you need to check is the block casting number , found on top aft end near to the bellhousing.
For 68 early cars , it is 3916321 , for late cars as of about February 68, it is 3935439. Also the block casted date is interesting, found on the pax side just above the oil pan about mid of the block. It is upside down and should read something like H 13 7 ( H for month , 13 is day, 7 for 1967 ) this being an example for a early 68. Casted date should be around 3 month b4 the car's build date, found on the drivers side door pillar.
The blocks stamp pad numbers read the suffix, explained already in previous thread and the car's VIN ( last 18S + 5 digit car VIN number )
If all this gives, the engine is most probably numbers matching.
For the heads, you need to remove the valve covers to get to the casted date and numbers.
The tri-power intake casted date is under the oil splash shield underneath the intake, not visible.
Nothing beats a 427 CI solid lifter square port engine setup.
Good luck. Günther
Safety Car
Joined: Feb 2006
Posts: 4,367
Likes: 59
From: FL
Determining Matching Numbers
One of the best web pages I have found is this one.
http://www.geocities.com/MotorCity/D.../matchnos.html
Go down about half way to see a drawing of an engine. The date code for a '68 big block are on the passenger side near the pan rail slightly ahead of the starter, not on the bellhousing flange, though.
The page doesn't give any numbers, just how to find them. The numbers are listed everywhere, but few tell you where each are.
http://www.geocities.com/MotorCity/D.../matchnos.html
Go down about half way to see a drawing of an engine. The date code for a '68 big block are on the passenger side near the pan rail slightly ahead of the starter, not on the bellhousing flange, though.
The page doesn't give any numbers, just how to find them. The numbers are listed everywhere, but few tell you where each are.
Safety Car
Joined: Feb 2006
Posts: 4,367
Likes: 59
From: FL
I forgot to add, the high performance 4 bolt main block used in the 435 hp and L88 will have the provisions for an oil cooler connection. See the two large plugs just over the oil filter.
Here is the two bolt main. You see the plugs are smaller.
You can see the date code location in this picture.
Here is the two bolt main. You see the plugs are smaller.
You can see the date code location in this picture.
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
That's interesting. I laways wondered what this plugs are good for.
But connecting a cooler to this, wouuldn't that bypass the oil filter.
Looks like one plug is on the inlet side of the filter and the other plug on the supply side.
Or how would everything be connected up.
I connected the oil filter to the filter sandwitch adaptor with internal thermostat, but with the plugs, would be a cleaner connection.
Günther
That's interesting. I laways wondered what this plugs are good for.
But connecting a cooler to this, wouuldn't that bypass the oil filter.
Looks like one plug is on the inlet side of the filter and the other plug on the supply side.
Or how would everything be connected up.
I connected the oil filter to the filter sandwitch adaptor with internal thermostat, but with the plugs, would be a cleaner connection.
Günther
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