BB guys found something interesting

[dukeboy_318]

Im buying a 77 400 motor from a fellow member on here and have been reading up on big blocks.  Ive heard that the late bb were thin wall castings and could be bored out anymore than .020.  however i found this on 440source.com disproving it.  just thought id pass it along incase someone else is in same situation as me.

http://www.440source.com/blockinfo.htm

[squeakfinder]

Yes. 440source.com website has been quouted many times on here. I have a 75 440 block that I had bored .060 over. I have over 700 miles on the build without any problems.

[dukeboy_318]

yeah i figure it had been but couldnt find it

[Mike DC]

 
The engineers claimed that the '76-78 castings were thinner walled because they were corporate-silenced from admitting that the iron in the '76-78 engine blocks had been weakened by about 10%. 

That's the real difference.  The wall thicknesses are the same but the iron is a bit weaker.  Earlier blocks are nice but it's not gonna make much of a difference for most mild motors. 

[supserdave]

And the later blocks have the strength ribs on the outside, so its kind of a wash.

[max]

unfortunately there has been alot of false or incorrect information about mopar engines over the years. even there so called newest versions of the mp engine books still have alot of that misinformation printed in them.