Help me decode my motor!

[1968_K20_4x4]

Looking for someone to help me figure out what motor is in my truck. The casting on the block on the drivers side towards the firewall is: 3956632. I read that this makes it a 307 from 1969. Is this right? Also, on the front pad on the passengers side there is stamped the code: VO428U5 (The last number is definately a 5 and not an S. I will post pics soon) I have not been able to find this code anywhere. If anyone can shed some light on what I have here that would be great!

[Joseph2001]

http://www.nastyz28.com/sbchevy/sblock.html

The z28 forums say you're correct.
You are in fact a 1969 307, as far as decoding the other numbers I have no clue, I'm still learning how to myself

[AussieinNC]

VO428U5

V Flint Michigan Engine Plant
04 April
28 28th

U5 I believe is a mis-stamp should be US

Which translates to US: 1979 305 LG4 H 160 4 Cutlass

The U5 mis-stamping issue has been around for a long time...

I believe it's possibly due to the use of "gang stamps" for engine number allocation.

Your engine is a transplant from all indications.

[bruceman1968]

You have a 1969 307. Your casting number 3956632 is for a 1969 to 1973 passenger car Chevelle Camaro Nova or Truck. I'm sure that you have a 5 stamped in your block, but when the 5 was stamped it was intended to represent a S. They did that all the time at the engine, transmission and rear end assembly plants. I's used as 1's are very common. lots of cases documented where letters were used as numbers or numbers used as letters. Sometimes a worker would misread a stamp and put it back in the wrong spot or a commonly used stamp would wear out and a similar looking letter or number stamp would be subsisted.
Your application code of U5 is meant to be US.
In 1969 US decodes to a 1969, 307cid, 200hp, manual trans, 2bbl carb, Truck motor.
If you want you can check your date code(opposite flange from your casting number) just to be sure.
EDIT: U5 followed by a letter was used from 1986 to 1990 for 350 truck motors. But your casting number eliminates that as a option.

[Joseph2001]

Originally Posted by bruceman1968

You have a 1969 307. Your casting number 3956632 is for a 1969 to 1973 passenger car Chevelle Camaro Nova or Truck. I'm sure that you have a 5 stamped in your block, but when the 5 was stamped it was intended to represent a S. They did that all the time at the engine, transmission and rear end assembly plants. I's used as 1's are very common. lots of cases documented where letters were used as numbers or numbers used as letters. Sometimes a worker would misread a stamp and put it back in the wrong spot or a commonly used stamp would wear out and a similar looking letter or number stamp would be subsisted.
Your application code of U5 is meant to be US.
In 1969 US decodes to a 1969, 307cid, 200hp, manual trans, 2bbl carb, Truck motor.
If you want you can check your date code(opposite flange from your casting number) but it's going to be a 69 date casting.

I knew the z28 forums didn't let me down. Their list of casting numbers has always been correct when I need it!

[1968_K20_4x4]

I am always amazed at the wealth of knowledge from the people on this site. Thank you so much for the great information! It all makes sense now and I really appreciate all your input guys. I love that there is always something to learn about these old trucks!

[1968_K20_4x4]

Originally Posted by bruceman1968

You have a 1969 307. Your casting number 3956632 is for a 1969 to 1973 passenger car Chevelle Camaro Nova or Truck. I'm sure that you have a 5 stamped in your block, but when the 5 was stamped it was intended to represent a S. They did that all the time at the engine, transmission and rear end assembly plants. I's used as 1's are very common. lots of cases documented where letters were used as numbers or numbers used as letters. Sometimes a worker would misread a stamp and put it back in the wrong spot or a commonly used stamp would wear out and a similar looking letter or number stamp would be subsisted.
Your application code of U5 is meant to be US.
In 1969 US decodes to a 1969, 307cid, 200hp, manual trans, 2bbl carb, Truck motor.
If you want you can check your date code(opposite flange from your casting number) just to be sure.
EDIT: U5 followed by a letter was used from 1986 to 1990 for 350 truck motors. But your casting number eliminates that as a option.

Thanks for all your help bruceman, you are obviously very knowledgeable about the casting numbers and I have some more questions for you. I have been thinking that someday I would like to upgrade to a 327. Everything else on my truck is all original, so I would really like to put in a motor that would be "correct" for the truck. It is a 1968 K20 with a 4 speed manual and a 4 barrel. How do I know what block casting code and stamping would be the proper one? I have seen the same casting codes that list as 327s, 302s and 350s. I have found a motor locally with a casting number of 3914678. The date code is C 15 8 and the block is stamped V0319YV. Would this be correct for my truck? If not, what should I be looking for? Thanks again for any input on this

[bruceman1968]

Originally Posted by 1968_K20_4x4

Thanks for all your help bruceman, you are obviously very knowledgeable about the casting numbers and I have some more questions for you. I have been thinking that someday I would like to upgrade to a 327. Everything else on my truck is all original, so I would really like to put in a motor that would be "correct" for the truck. It is a 1968 K20 with a 4 speed manual and a 4 barrel. How do I know what block casting code and stamping would be the proper one? I have seen the same casting codes that list as 327s, 302s and 350s. I have found a motor locally with a casting number of 3914678. The date code is C 15 8 and the block is stamped V0319YV. Would this be correct for my truck? If not, what should I be looking for? Thanks again for any input on this

Your welcome, happy to help when I can.
3914678 = 302, 327, 350 in 1968
C 15 8 = March 15th 1968 Casting date
V0319YV = Flint, March 19th, Assembly date,
YV = Truck motor, 327ci, 240hp, Th400 trans, 4bbl,
Your truck is a 1968 right? The motor in post 1 is a 69. Is that original to your truck? If so we need to check the casting date. The books aren't always right. Also engine casting dates are always the actual year and month cast. Model years on trucks/cars are split. Some 68 model trucks were built in Sept, Oct, Nov, or Dec, of 67.
If your truck is a 1968 then you won't get much closer to correct than the motor you located. Your located 1968 327 motor was cast march 15th of 1968. Your truck could have been built before that. How close are you trying to get?

[Steeveedee]

I recall seeing somewhere that the 307 had the motor mount holes in a different location from all other small blocks. I don't remember where, but it stuck with me, because I had always thought that a small block = a small block, after Chevrolet went to those mounts from the front horse collar set up. The motor mount is the same, but the frame perches were different. If true, it's something that might need to be addressed to keep the engine level.

[bruceman1968]

Also the YV 327ci, 240hp, Th400 trans, 4bbl, motor you found was originally married to a Th400 auto. If you want one that was married to a manual then your looking for a YX stamped suffix code motor. Depends on how close your trying to get.

[1968_K20_4x4]

I am assuming that the motor in my truck is not original because of the casting number on the block, which decodes it to a 1969 motor. My truck is a 1968 according to the vin. I unfortunately do not have the spid, build sheet or any other info to indicate what motor the truck came from the factory with, other than according to my vin number it was a v8 truck. I do not know the build date of my truck nor do I know how to check it. If this motor I have found for sale originally came in a truck with the th400 I think I will keep looking until I find a block with a YX stamping to make it correct to my truck. Or a whole 1968 parts truck with a 327 in it. Like I say I don't need a new motor as my 307 in the truck is currently running well with no issues, I'm just keeping an eye out and if I happen to find the right 327 motor that matches my truck then I would be interested. Also I will keep that in mind about the 307 engine mounting blocks. Bruce where did you find the information about the engine stamping codes and what they decode to?

[bruceman1968]

I have a book from MSA-1 by Mark S Allen for small block Chevy suffix codes. I just now looked for the MSA-1 website and can't find it anymore. I don't know why, but it looks like you can still find the book on amazon. Jegs and Summitt used to carry it. They still might. There's also a MSA-1 book for Big Blocks. One for I-6 Chevy's as well as one for Buick, Pontiac, Ford etc. These are small books you can carry in a shirt pocket. Sometimes there are errors. Always best to check a couple of sources. GM documentation is the best source but it is expensive and difficult to find. There are several other books for Chevy engine codes that you can find with a quick search.
Here is a link to the Z28 website that has a pretty good list of suffix codes as well as other Chevy info. This link goes to the page for your 68, 327 info.
http://www.nastyz28.com/gm-chevy-cod...-suffix-10.php

I also found another code that fits your application. YL

If you want to find the casting date code on your 307, here is a pic that will help.

[MARKDTN]

Originally Posted by Steeveedee

I recall seeing somewhere that the 307 had the motor mount holes in a different location from all other small blocks. I don't remember where, but it stuck with me, because I had always thought that a small block = a small block, after Chevrolet went to those mounts from the front horse collar set up. The motor mount is the same, but the frame perches were different. If true, it's something that might need to be addressed to keep the engine level.

No, the mount locations on a 307 are the same as the other large journal blocks.

[JimmyS10]

Not trying to hijack this thread but I'm new to these forums and don't know how to post my own yet. But...I'm learning. Can someone help me? I found lots of info on SBC and BBC but very little on V6.

Talk about frustrating! Anyone called GM recently? After an hour and a half on the phone with 6 departments I'm no further in my quest than I was earlier. Hopefully someone on this board can help.

I am in the process of building a hot rod 28 roadster. I've decided to use a GM V6 powerplant for a number of reasons. Anyway, I was able to pick up a V6 pretty cheaply. Before putting in the roadster I want to rebuild it. In order to rebuild it I have to identify it so I get the correct parts. Seems simple so far, right? Well, everyone wants the year, make, model and VIN of the donor vehicle. I tried to explain to GM that is what I am calling them for. If I had that, I wouldn't need to be calling. Anyway, the VIN would only be valid IF the engine was the original for that vehicle. So, I'm looking for info from some of you more knowledgeable folks. Here's what I have and am trying to identify:

GM V6 4.3 L 4bbl carb
Engine ID = T1121UTC
Block Cast = 10105867

I know T = Tonawanda Buffalo, NY
1121 = 11/21
It appears to be an 87-91 based on the casting number.

Can anyone help identifying this engine further? Thanks in advance.

[1968_K20_4x4]

Thanks again Bruceman for all the info. I have recently found another motor for sale locally with a casting number of 3914678. The seller says it is a 1968 327. The motor has been rebuilt by a machine shop, however it still requires heads and an intake to make it complete. I asked about the date code and the seller indicated that it came out of a 1968 Caprice estate wagon however the motor has been "decked" so the original stamping is no longer there. However it is the correct year and size of motor I have been looking for, and he is selling it for what I believe to be a fair price for a freshly rebult motor so this is the route I am now going to take. I appreciate all the information... now I have to start a new thread to begin researching what heads I want to run on this motor!