The Dodge Challenger Message Board

How many like that heading???
Automotive quality control and acceptances has a high standard today, unfortunately it has not always been like that. Many producers have released material outside the tolerances, but with some information about the deviation. Mopar was no exception in that case. I picked up following information on a Swedish forum, I don't know where it was published first.

I know there are alot of Mopar Engine builders out there so here is some important things to look for when digging up some of those old blocks. Alot of people do not know that many engines were put into cars with factory defects and there are easy ways to find out what they were. For instance if you have an engine and it has a 3/8' maltese cross stamped in the same area as for instance the 383, 440 stamp is located, this would indicate that the engine had problems with the main or rod bearing from the factory and some of them are over or under normal size. If you do see the maltese cross you would then look at the 3rd counterweight on the crank to find out what the problem was. If it says for instance m-2-3 that would mean that the Main Bearings on the #2 and #3 position are .001' Under/Size and the rest are standard. If the engine has a maltese cross and an X it would indicate .010' Under/Size bearings. If the block has an 'A' stamped at the same position it would indicate a .020 Over/Size Cylinder bore. Hard to believe these would be sent out. If a 3/8' tall diamond is found this would indicate .008 Over/Size lifters. If an O.S. is found on the Single bolt boss on the end of the head, this would indicate .005 Over/Size Valve stems. These were common stamps for all big blocks including Hemi's. If you need more info on Small Blocks or Six Cylinders let me know. I think I still remember all of those markings also. Hope this may help save some problems down the road.

Richard Williford
V.P. Marketing & Sales
DragRaceResults.Com
dragracestore.com
dragracestore@hotmail.com

It is a bit harsh to say they were sent out with "defects". These are not defects. They sometimes just have slightly different sized parts from the norm.

Deviations would be the correct English word being "a difference beween an observed value in a series of such values and their arithmetic mean."

Sometimes a casting or forging might not be perfect but if all it took was a little extra machining to make it good then it was cost effective to do that.

By putting the markings on the block it was also obvious to any engine rebuilders in the future that some bearing sizes etc were a slightly different size than standard. These markings have always been common knowlege and this information is freely available in the workshop manual.

However before you all go out and check your engine block for "defects" you should be aware that engines like this are quite rare and you seldom come across one.