360-1 Casting better?

RustyRatRod said
I've sonic tested a lot of blocks looking for a pattern and there really is none.....that I found anyway. I did find some thick ones. I will say most were 73 and back but there were some up into the late 70s that were thick. This was before I knew anything about the - numbers, so I did not include that. The 77 360 I punched .070 over for a 416 was thick. I don't remember the numbers as this was back about 1998 or 1999. Decent sonic testers are not too expensive now. If anyone builds any number of engines at all, it's a good tool for the tool box.

Agree. 440 Source tested a whole bunch of blocks (granted, big blocks but I would assume the same logic would apply) to see if there was any pattern to the early vs late or "thinwall" blocks. They found that if anything the later blocks were better. 440 Source.com Everything you've ever wanted to know about blocks and more....

They also said this about the tooling numbers here 440 Source.com - Info on Chrysler's casting and part numbering system

"While we are on the subject of casting numbers, often there will be what is known as a "tooling revision number" or a "dash number" after the casting number. A 1968 440 block, for instance, might read 2536430-12, or sometimes there will just be a space, such as 2536430 12, or sometimes 253643012. While 2536430 would be the casting number, the 12 would be the tooling revision number, which indicates how many times the tooling (core molds) have been reconditioned back to the proper specifications or modified to include improvements. After so many "pours" the tooling gets worn and needs to be reshaped or reconditioned. So theoretically, higher numbers will be later dates and have any casting improvements incorporated into them. The only problem with this theory is that engines were produced in such volume that many many different sets of tooling were used concurrently to meet the necessary output. So while some may have lasted for quite a while, (in which case you will find later dates with earlier revisions) some got worn quickly or damaged and needed to be revised after a short time. So while in some cases, parts with later numbers may include some improvements the earlier parts may not have, on a practical level, it means nothing as far as the quality of the piece. In other words, don't waste your time looking for an early or late tooling revision number. Blocks, heads, water pump housings and many other cast parts have revision numbers as well.

Another thing to keep in mind is that tooling revision numbers have absolutely nothing to do with core shift, which is when the core molds move around as the cast iron is poured. That will vary depending on how much the molds moved in the specific piece (usually engine block) you are talking about, and the only way to tell if there is enough material in the cylinder walls is to sonic check the specific block you are going to use. As you probably learned from our "Everything you've ever wanted to know about engine blocks" page, (and if you haven't read this page yet, you should) there are no thinwall blocks, however we have found core shift to be less prevalent in the later blocks, perhaps due to improvements in casting technology over the two decades the engines were in production."

So, kinda sounds like a crapshoot to me. If you're building a high horsepower block or going for a larger overbore, have it sonic tested.