How do you read the numbers on you block. I heard that "10" at the end of the serial means it is a 4 bolt main, and 5 or 10 beside the timing chain identifies the tin and iron content (when the block was forged). Is there a list of all the numbers used for the blocks especially a 350 sbc from 1973.

Cheers Mack

I think your referring to a "010"  however that doesn't mean it's a four bolt main, the only way you can tell that is to pull the pan and look.  For some casting numbers go to mortec.com they have em all.

The "10" on the end of the casting number has no signifcance toward identifying a 2 bolt or 4 bolt block. The same casting number is used for both, however, the block part number will be different 2 versus 4 bolt. Problem is, most blocks only have a casting number on them, so you have to drop the pan and look.

The numbers adjacent to the timing drive denote the amount of tin and or nickel added to the iron of the casting. Tin adds to the flowability (if that's a real word) of the iron which improves the iron's ability to fill the mold. We get better, stronger parts the factory has fewer QA rejections. Nickel adds strength, while the casting is not stainless steel, it is cast iron, nickel is a major alloying element of steels that makes the difference between ordinary mild steel and stainless steel. It adds a lot of strength to the cast iron and also provides some rust resistance through a process called self passivation. Nickel is used in heavy-duty blocks intended for high performance use and some truck blocks get a dose, most ordinary passenger and light truck blocks don't get any.

Go to Mortec for lots of casting number data.   http://www.mortec.com/

Bogie

Thanks for the casting numbers. Do you know of proven engine combos?

cheers

Bog:

What do you know about these so-called "high nickel and/or tin" sbc castings?  I've been involved in bench racing discussions on the topic; yet, have only read of their existance once in a publication (Dave Emanuel's Small Block Chevy Performance).  Net, there's mixed beliefs on the subject.

About six years ago, I spent a good part of a year looking for one and located a donor '69 DZ302 block with a raised "010" casting mark near both engine mounts and under the timing chain cover.  I never had any luck locating an "020" or "010/020" casting.  Possibly because they had all been snatched up! 

I understand the 'theory' behind the castings (nickel and/or tin mixed with iron). 

Yet, what's your point of view...fact or fiction?

* I presume 'fact' based on your previous post.

I have rarely seen the 010/020 blocks most that I have seen are pre 1972 302s and the 400 that was to go into the Z-28 but didn't. The big block 427s had nickel. Most anything Oldsmobile had nickel, but we're talking Chevy here. I think most nickel blocks go to the pros pretty fast. The BowTie and Rocket Blocks are probably the best bet for finding some nickel, but they don't carry any ID as the production blocks do. A sure fire test for nickel is to pick a spot and polish it, if it pulls up like a mirror, there's nickel in the mix, if it stays dull and gray even though smooth, it's iron.

Amounts of tin and nickel are very small it's 1 or 2 percent, not 10 or 20 percent as often thought. Motown uses 5 percent in their castings, talk about a block that dulls tools.

There's a place of argument where some folks take the position that a thick walled gray iron block is superior to a thin wall nickel block. I guess the real answer has to do with weight distribution of the vehicle as much as anything with block strength of the two positions. Most racers would go for a thick and nickel block.

Bogie

Hey, where can i get a copy of Dave Emanual's "Small Block Chevy Performance"?  

Google.  

What about the old big block Caddy engines? I've heard 4% as well in the 500 and 472. Is this true?

Brian

Sort of, these are extremely thin wall castings. Early blocks had none to little nickel and were prone to cracking arond the cylinder bores. GM added more nickel in second year and on production which greatly reduced in-service cylinder wall cracking. However, all these engines are right on the structural limit of bore wall thickness and really can't accept an overbore beyond .005 inch with any reliability, which is really nothing more than a hone clean up of the bore. They're not really suitable for performance work as significant power increases quickly reduces cylinder wall life. But in stock or near stock form they're mighty nice power plants for swaps where lots of torque is desired such as highway towing.

Bogie

Hey oldbogie

How would I get those casting #s?

I'm the new guy who just found out about this site

and I'm thrilled to find all this info.

  Thanks

Try these

Bogie

http://www.kendrick-auto.com/chevrolet_head_casting_number_re.htm

http://www.holisticpage.com/camaro/parts/codes.htm

http://www.mortec.com/

http://www.racecheep.com/Castings.html