Why not a 413 ?
Industrial/truck blocks have extra cold weather ribbing on the outside of the blocks.
This is from 440 Source.
Everything you've ever wanted to know about blocks and more...
Written by Brandon Nicholas in 2003.
Copyright
www.440source.com
If you haven't read our page on
An explanation of Chrysler's part and casting number system, be sure to check it out also.
Blocks are one of the most misunderstood aspects of building a big block Mopar engine. Never has there been more misinformation, propaganda and rumors floating around. In the many years we have been involved with the big block Mopar engine, we have seen and owned many many hundreds of used core engines. We have used this opportunity to try and keep records as much as possible as to different advantages and disadvantages that various blocks offer. All the facts listed below are the result of our independently testing, measuring, sonic checking or otherwise gathering information directly from original sources: either the blocks themselves or the original factory drawings (blueprints) that Chrysler used to manufacture the blocks. This eliminates all chance of secondhand information, rumors, marketing or sales talk, etc. Hopefully this page will help hobbyists, restoration experts, and racers decide which choice of block is best for them.
First, let us address the biggest myth of all:
For many years it was thought that late model blocks were thin wall and should not be bored more than .030 over.
On page 198 of the Mopar engines manual, (the 8th edition) in the "B-RB Engines (block) section, it states: "The 1976-1977-1978 blocks for the 400 and 440 are a thin wall casting design. As such they shouldn't be overbored more then .020." This quote can now be found on page 58 of the new "Big Block B/RB Engines book from Mopar Perfomance, part # P4876825
Two pages later, (pg. 200) under "Boring and milling specifications," the manual states: "...The newer blocks (1975-1978) should only be bored .030" max., because they are thin wall castings. This quote can now be found on page 64 of the new "Big Block B/RB Engines book from Mopar Perfomance, part # P4876825
Then, in the May '98 issue of Mopar Performance News, in an article titled "The Big Block Story" on page 16, it states: "The newer production 440 blocks, '73-4 to '78 are thinwall cast, so you can only bore them .020"..."
So, as you can see, even these multiple sources of info which come straight from Chrysler engineering contain different information. What is the Mopar enthusiast supposed to think? Are the thinwall blocks from 76-78, or are they from 73-78? Can you bore them .030, or is .020 the maximum? We will answer all these questions once and for all based on scientific fact. The purpose of citing these books and articles is not to make Chrysler/Mopar Performance look bad. As racers and hobbyists, we are grateful for the resources and aftermarket parts that Chrysler makes available. However, it does demonstrate how even someone who does their research could be easily confused. So, it is to the benefit of everyone involved to help spread information which is known to be true, even if goes against popular thinking.
So what is the truth? Get ready for this.
There is no such thing as thinwall blocks. They DO NOT exist.
We have sonic checked over 50 blocks, and have found absolutely no evidence that later model blocks have cylinder walls that are any thinner then earlier blocks. In fact, we have found later blocks to have less core shift, meaning the cylinder walls are of a more uniform thickness all the way around. This makes perfect sense, considering that B engines were in production for over 2 decades. During this time, it would be expected that there would be small improvements in the technology of casting processes, quality control, etc, which would help create a better product.
There was also an article from Mopar Action magazine by Andy Finkbeiner of AR Engineering in which they sonic check 20 blocks and come up with the same findings we did. They also explain how statistically 20 blocks is enough of a sample to estimate the rest of the 440 blocks out there. We've tested over 50 with the same results. This article also has some great info regarding hardness of the iron used, in which they find that the earlier blocks do have slightly harder cast iron, by about 10%.
Another issue is block weight, or the quantity of cast iron which is actually used in the block. Like the Mopar Action article, we have weighed many blocks and have found later blocks to weigh more, or have more cast iron in them. Since the reasoning behind thin wall blocks is that the factory used this practice in the late 70's to save money on iron (which is a known fact with SB Chevy engines), the fact that later blocks weigh more shows that Chrysler had no intention of using less iron to save money. Which is great news for us racers and performance enthusiasts.
So, the bottom line? Save and use those late model blocks. And go .060" over with 'em all day long. Also on that note, we know of several machine shops that have been going .060" with late model blocks for over 20 years with no problems.
