Casting Numbers For Big Block Chevy: Everything You Need To Know

Certainly, the aftermarket has done a fantastic job of producing performance engine blocks for chevy. However, there are instances when an aftermarket engine block is not what you need. Sometimes an original engine block is what you require, either for a thorough restoration or a low-cost rebuild.

Cast or stamped numbers are used to help identify each Chevrolet Big Block engine. The big-block engine casting numbers serve as a means of distinguishing an engine block by designating the casting number, the year of manufacturing, and the CID (cubic-inch displacement).

Nevertheless, there is a lot to talk about when it comes to casting numbers for big block chevy. So without any further ado, let’s get started.

Casting Numbers For Big Block Chevy: Chart

Before we even dig into the details, we thought that a chart would certainly come in handy. If you know all the ins and outs, then only this chart will help you identify everything you need to know. So here it is!

Casting NumberYearCubic-inch displacementHP/RPO/Remark
3402201972-76     427tall truck
345014       1974-86     454   truck
3462361974-76     454   215, 2 bolt
3590701974-90     454   truck
3619591973-85     454   car & truck
3647761968-84     427tall truck
3647791968-88     366tall truck
4734781968-84     427tall truck
37828701968-76     427tall truck
3855061    1965-67     396None
38559611966-67     396325, 360, 2 bolt
38559621965-66     396360, 375, 425, 4 bolt
38559771965-67     366tall truck
38669611966-69     396Chevy, Chevy truck
38699421966-67     427390, 425, 2&4 bolt
38738581966396375, 4 bolt
39024061967396325, 350, 375, 2&4 bolt
39024661965-67     396None
39043511967427385, 390, 400, 425, 430, 435, 2&4 bolt
39043541966-67     366tall truck
39163191968-85     366tall truck
39163211968427385, 390, 400, 425, 430, 435, 2&4 bolt
39163231968396325, 350, 375, 2&4 bolt
39183191966-70     366Chevy truck, GMC, tall truck
39255211968-85     366tall truck
39283191969-73     366GMC, tall truck
3935439    1968-69     427335, 390, 400, 425, 430, 435, 2&4 bolt
39354401968-69     396265, 325, 350, 375, 2&4 bolt
3937724    1968-85     366tall truck
39377261968-84     427tall truck
39552701969427335, 390, 400, 425, 430, 435, 2&4 bolt
39460521969427430 ZL-1, 4 bolt, aluminum
3955272    1969396/402    265, 325, 350, 375, 2&4 bolt
39552741968-85     366tall truck
3955276    1968-84     427tall truck
39635121969-71     427335, 390, 400, 425 COPO, 430, 435,
39635131973-76     454345, 360, 365, 390, 425, 450 2&4 bolt
3965440    1968-69     454215
39654491968-72     396None
39655401968396None
3969854    1969-72     396None
39698581968-84     396/402    240, 265, 300, 325, 330, 350, 375
39992891972-78     454360, 2&4 bolt
39992901972427tall truck
39992931968-85     454215, 235, 240, 270, 2 bolt, car & truck
39992941968-84     402240, 2 bolt
62721761968-76     366Chevy, GMC, tall truck
62721771972402210
62721811973-76     427tall truck
1401544    1975-87     454truck

What Is A Casting Number?

When purchasing and installing new parts in their engine, car owners must have a thorough understanding of casting numbers. These engraved digits, which are frequently visible on an engine block, portray a range of useful information.

They are; the year of manufacturing, the CID (cubic-inch displacement), and the place of the engine’s production.

This number enables the vehicle’s owner to buy parts that are compatible with the model year and manufacturer of their engine. To avoid problems later, especially if you intend to replace parts or perform some repairs yourself, it is crucial to research your car and match the numbers.

Where Are The Casting Numbers Located?

Out of this big block, searching for the casting numbers can get tricky. Moreover, there are other things as well which can get you confused.  However, it’s not really hard when you know where exactly to look.

At the start, pay attention to the engine’s front. On the front pad, which is essentially the passenger side front, there may be a casting number. However, there is a possibility that it will become covered and impossible to locate.

As a result, the back of the block is where you should head next. In essence, it is the block on the driver’s side. You will find a 6 or 7-digit number here. So you probably have found the casting number you were looking for.

What Are The Alphabets Beside The Casting Numbers?

Individual letters like “GM” or “CFD” for the Central Foundry Division may occasionally be seen on blocks. However, they are not a part of the block casting number.

Additionally, the capacity of the engine is shown in letters rather than alphabets on the recent blocks. So you don’t need to depend on the alphabet to get to know about it.

How To Read A Dirty Big Block

Before you can read them, there can be a ton of grime and grease covering them that has to be removed. It can make it more difficult to read them, especially when they are positioned inside  your vehicle. Thankfully, the casting numbers are on the rear of the block.

You can always use a mirror and a little perseverance to reach and view the difficult-to-reach spots. On the other hand, some people will additionally rub the dates and numbers on the block’s back ledge with a piece of aluminum foil.

Here’s Another Way You Can Do it! Check Out This video

Conclusion

To conclude, that was all you needed to know about casting numbers for big block chevy. Yes, it can be intimidating if you haven’t worked with it before. However, once you have taken the block out and found out the casting number, it’s all straightforward from now on.

Simply note down the engraved numbers and match them with the chart to find  the year of manufacturing, and the CID (cubic-inch displacement). Yes, they are extremely vital when you have something to replace in your Chevy.

Nevertheless, you might come across a dirty block where the numbers aren’t that visible. For that, you can use rub the dates and numbers on the block’s back ledge with a piece of aluminum foil.

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