Author Topic: Where's the date code on a 403 Oldsmobile?  (Read 517 times)

Maxthe222

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Where's the date code on a 403 Oldsmobile?
« on: December 30, 2021, 08:05:01 PM »
Hey gang,

How do I actually determine the date code a 403 Oldsmobile block was cast?  If the VIN has been re-stamped or has faded away, how can I tell? There is a clock on the back of the block, there's random numbers on the heads besides 4A, but what on the intake is the date code here? The number 279? Isn't that just the day of the year the intake was cast? How do I know if it was a '77, '78 or '79? This does have the vertical 77-78 water intake, but that could have been changed at some point.

1987 T/A GTA L98
1979 T/A Y84 WS6
1979 F/A W72 WS6
1978 T/A L80 WS6
1978 Formula L80 W50
1971 Formula 400 4-Speed

olds403

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Re: Where's the date code on a 403 Oldsmobile?
« Reply #1 on: December 30, 2021, 08:52:36 PM »
There are two 403 blocks 403 and 403X.  On the block by the dizzy hole is the block 3 digit date code.’
The vin is on the drivers front under the cylinder head.  You can not figure out if the block is a 77 78 or 79. 
At 45 years old - finding a good block is hard enough.  The cylinder heads are date coded and if still on the block you can figure out the year.  Hope that helps

langss

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Re: Where's the date code on a 403 Oldsmobile?
« Reply #2 on: December 30, 2021, 10:04:39 PM »
There are two 403 blocks 403 and 403X.  On the block by the dizzy hole is the block 3 digit date code.’
The vin is on the drivers front under the cylinder head.  You can not figure out if the block is a 77 78 or 79. 
At 45 years old - finding a good block is hard enough.  The cylinder heads are date coded and if still on the block you can figure out the year.  Hope that helps
Just for the sake of curiosity, what does a running 403 go for.

olds403

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Re: Where's the date code on a 403 Oldsmobile?
« Reply #3 on: December 30, 2021, 11:16:47 PM »
The block $200 or so.  Running $400-$500

langss

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Re: Where's the date code on a 403 Oldsmobile?
« Reply #4 on: December 31, 2021, 12:37:01 AM »
The block $200 or so.  Running $400-$500
Seriously....I had no idea. Thank You.

Re: Where's the date code on a 403 Oldsmobile?
« Reply #4 on: December 31, 2021, 12:37:01 AM »

Maxthe222

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Re: Where's the date code on a 403 Oldsmobile?
« Reply #5 on: December 31, 2021, 05:12:06 PM »
There are two 403 blocks 403 and 403X.

403X? What's the difference?
1987 T/A GTA L98
1979 T/A Y84 WS6
1979 F/A W72 WS6
1978 T/A L80 WS6
1978 Formula L80 W50
1971 Formula 400 4-Speed

Maxthe222

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  • Posts: 868
Re: Where's the date code on a 403 Oldsmobile?
« Reply #6 on: January 01, 2022, 04:30:50 PM »
Ok, here are the heads, how do I figure out what year/date these are?



1987 T/A GTA L98
1979 T/A Y84 WS6
1979 F/A W72 WS6
1978 T/A L80 WS6
1978 Formula L80 W50
1971 Formula 400 4-Speed

olds403

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  • Posts: 2016
Re: Where's the date code on a 403 Oldsmobile?
« Reply #7 on: January 03, 2022, 10:46:49 PM »
No pictures

Maxthe222

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  • Posts: 868
Re: Where's the date code on a 403 Oldsmobile?
« Reply #8 on: January 04, 2022, 10:32:08 PM »
No pictures

Oh you're kidding, they didn't upload lol! That would probably help lmao









1987 T/A GTA L98
1979 T/A Y84 WS6
1979 F/A W72 WS6
1978 T/A L80 WS6
1978 Formula L80 W50
1971 Formula 400 4-Speed

Re: Where's the date code on a 403 Oldsmobile?
« Reply #8 on: January 04, 2022, 10:32:08 PM »
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