Author Topic: 403 block casting numbers  (Read 15794 times)

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Offline Helter80

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403 block casting numbers
« on: July 15, 2008, 06:21:16 PM »
i have an olds 403. on my clyinder heads they say 4A, the casting number for the block in back of the water pump is 557265   4B
i have looked at some websites and am really confused. i just would like to know what year the engine is, and if the cylinder heads year match the year of the block because of the 4A and 4B difference. i know nothing about olds engines casting numbers.
thanks guys!
www.transamplus.com
Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

Offline bobg

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Re: 403 block casting numbers
« Reply #1 on: July 15, 2008, 07:24:53 PM »
Your casting number shows a 77-79 block and the head being a 4A stamp is normal, it is proper for 77-79 403. I an not sure, but I believe the 4a is the only head to come on the 403. You can pinpoint the date of manufacture for head and block by decoding the date codes, but your block, head combo is correct for the 77-79 403.
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79 gold 400 4spd w72 T top
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Offline Joker (告r茺agon)

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Re: 403 block casting numbers
« Reply #2 on: July 16, 2008, 01:09:26 AM »
Bob is right that the 4A heads are the only head available tor the 403. But there is not date code on them. However, for the block this should help.

Larry


Offline Helter80

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Re: 403 block casting numbers
« Reply #3 on: July 16, 2008, 07:58:05 AM »
Bob is right that the 4A heads are the only head available tor the 403. But there is not date code on them. However, for the block this should help.








awesome! thanks larry.
-Rob
www.transamplus.com
Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

Offline Helter80

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Re: 403 block casting numbers
« Reply #4 on: July 18, 2008, 02:03:00 PM »
where are the date codes on the 403? i can't seem to find them. i know on chevys, they are alongside the casting number on the back of the block just above where the transmission mounts. i can't see anything back there on my 403
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Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

Offline Joker (告r茺agon)

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Re: 403 block casting numbers
« Reply #5 on: July 18, 2008, 03:00:11 PM »
Well, the second digit on that VIN code will be the last year in the date it was built. Back by the distributor hole (towards the passenger's side) there should be a number between 1 and 365. That will be the day of the year. (i.e. if your year code is 9 and the day code is 162 would mean the 162nd day of 1979.)
Larry


Offline Helter80

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Re: 403 block casting numbers
« Reply #6 on: July 18, 2008, 04:45:34 PM »
Well, the second digit on that VIN code will be the last year in the date it was built. Back by the distributor hole (towards the passenger's side) there should be a number between 1 and 365. That will be the day of the year. (i.e. if your year code is 9 and the day code is 162 would mean the 162nd day of 1979.)




ah, ok cool. i'll check out the date code, but i have a problem with the vin# on the engine. it is not there anymore.
i bought the engine as a rebuilt unit from Liberty Engines in PA, and i guess they wore off the vin# because unfortunetly its not there. thanks for your help
www.transamplus.com
Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

Offline Helter80

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Re: 403 block casting numbers
« Reply #7 on: July 18, 2008, 05:07:16 PM »
actually wait, i had to wipe off a TON of dirt and stuff off of the engine. also my eyesight isn't that great, but the VIN number is there. 39M155495    and the date code is 237.   how do i decode the VIN# ?  i'm assuming its a 79 motor, but i'm curious as to what the other digits mean, especially the "M"
www.transamplus.com
Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

shakerz

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Re: 403 block casting numbers
« Reply #8 on: July 18, 2008, 05:26:57 PM »
actually wait, i had to wipe off a TON of dirt and stuff off of the engine. also my eyesight isn't that great, but the VIN number is there. 39M155495    and the date code is 237.   how do i decode the VIN# ?  i'm assuming its a 79 motor, but i'm curious as to what the other digits mean, especially the "M"

i bet that 'M' is actually an 'N'. the vin stamp on those 403 cast iron, machine faced tags get faint after awhile. I'm betting it is 'N' = Norwood assembly plant. 'L' is the other one for Van Nuys, I believe. The third digit. The second digit is for year '9' =79. I'm at work, Helter, and dont have my usual resources, but I think the first digit indicates application. The last 6 digits are important too =the vin sequence. Should match the last 6 of your dash vin plate and the last six of ur vin stamp on firewall. U dont have to remove a/c box to visualize, btw, just ur blower motor -6 little 5/16" hex screws.

the more I think about it, there was an 'M' assembly plant code. Lansing, Michigan?

good luck!
steve
« Last Edit: July 18, 2008, 05:28:39 PM by shakerz »

Offline Helter80

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Re: 403 block casting numbers
« Reply #9 on: July 18, 2008, 06:01:37 PM »
haha oops, i just noticed now on that picture above with the 403 that Larry posted. yeah so my engine is a 1979 403 built in the Lansing, Michigan plant on August 24, 1979.  my car was built in June of 1979. --i knew it wasn't the original motor. i guess its kinda cool to know that the year of the engine still matches the year of my car
www.transamplus.com
Rob


79 Trans Am- Nocturne Blue,T-Tops,403,Camel Tan Deluxe Interior

shakerz

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Re: 403 block casting numbers
« Reply #10 on: July 18, 2008, 07:10:09 PM »
haha oops, i just noticed now on that picture above with the 403 that Larry posted. yeah so my engine is a 1979 403 built in the Lansing, Michigan plant on August 24, 1979.  my car was built in June of 1979. --i knew it wasn't the original motor. i guess its kinda cool to know that the year of the engine still matches the year of my car

yep I agree, the engine date code from same year as car makes it as correct as possible without total #'s match. i was lucky enuff to find the correct heads on ebay recently for my 71 formula. 96cc 6x heads date casted from late 1970 which Pontiac often did use heads and such casted in the previous year.

steve

Offline Joker (告r茺agon)

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Re: 403 block casting numbers
« Reply #11 on: July 19, 2008, 12:58:11 AM »
actually wait, i had to wipe off a TON of dirt and stuff off of the engine. also my eyesight isn't that great, but the VIN number is there. 39M155495    and the date code is 237.   how do i decode the VIN# ?  i'm assuming its a 79 motor, but i'm curious as to what the other digits mean, especially the "M"

i bet that 'M' is actually an 'N'. the vin stamp on those 403 cast iron, machine faced tags get faint after awhile. I'm betting it is 'N' = Norwood assembly plant. 'L' is the other one for Van Nuys, I believe. The third digit. The second digit is for year '9' =79. I'm at work, Helter, and dont have my usual resources, but I think the first digit indicates application. The last 6 digits are important too =the vin sequence. Should match the last 6 of your dash vin plate and the last six of ur vin stamp on firewall. U dont have to remove a/c box to visualize, btw, just ur blower motor -6 little 5/16" hex screws.

the more I think about it, there was an 'M' assembly plant code. Lansing, Michigan?

good luck!
steve

Right, M would be Lansing MI. ;)
Larry


shakerz

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Re: 403 block casting numbers
« Reply #12 on: July 19, 2008, 10:31:06 AM »
Right, M would be Lansing MI. ;)

thanx larry. next time i'm up that way, all the guys who pumped out t/a's in lansing...the beer's on me. :)

steve

Offline Joker (告r茺agon)

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Re: 403 block casting numbers
« Reply #13 on: July 19, 2008, 01:28:50 PM »
No T/As were built in Lansing so your tab will be pretty low. ;)   That's where the engine was built.
Larry


shakerz

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Re: 403 block casting numbers
« Reply #14 on: July 19, 2008, 03:58:14 PM »
No T/As were built in Lansing so your tab will be pretty low. ;)   That's where the engine was built.

just testing u, larry. ok, i'll tell hitman u can still post here. j/k :)