Original Motor?

[Barrie]

Purchased a 72 Blazer as a project. Appears the previous owner was trying to make 1 good truck from 2 or 3. Small block in this truck either a 307 or 350, not sure yet. Is there some way to determine from serial #'s or build sheet if this motor is the original? Not an issue for me either way just trying to confirm.

Thanks, Cam

[eighty-seven]

I think early 70's 350s had 010 in the last 3 numbers of the serial.

[SS Tim]

If you have a protect-o-plate it will have the engine asembly number and suffix code.
If you have a build sheet it will have the engine suffix code and an assembly date the engine assembly number should preceed.

The production block has a stamped assembly number indicating plant, date and exact engine model. This is located on the right deck just forward of the head. Unlike a car the actual VIN is not stamped into the engine.

This neeeds to be cross confirmed by the block casting code and date.
Both of these are cast into the block.

[Barrie]

Thanks to both replies, I will look an see what I can find.
Cheers, Cam

[bruceman1968]

Barrie, Here is a photo to help you locate the numbers.

[Barrie]

Great, thanks.
Cheers, Cam

[Senorx]

I was also wondering if the 350 in my 71 K5 is original. I found the following code on the front of the block on the passenger side.

V0521TBG

V = Flint, MI.

0521 = May 21st

TBG = 71' 350 Truck

Did I de-code this correctly? Where can I locate an actual serial number that matches then truck VIN#? It's looking good so far. At least the number suggests 1971. My truck was made in June 1971 as per the sticker in the door jam.

[71swb4x4]

Senor X, as Tim mentions the VIN is not stamped on the motor of trucks.

[SS Tim]

Closest you will come is having an authentic Protect-O-Plate matching the engine assembly number to your VIN. Anything less is a guess or in the case of sellers, wishful thinking. Then it is a matter of how far you want to go as to determining how "original" your motor is.

[Senorx]

Roger that. I'm gonna call it the original engine. The year of the engine and my K5 are both 1971. My SPID also states a 350 CID engine.