[Hassan]

I own a 440-6 chally that is supposed to have been blueprinted and rebuilt. what is the difference between a blueprinted motor and stock 440?

[dave-r]

Blueprinted means that every part has been carefully machined to bring it as close to sepecification as possible. All clearences are checked and adjusted, All surfaces machined to perfection etc.

On a production line, back in those days, you got quite a wide tolerance due to human error and the fact that the cutting machines used were just not that accurate. Plus they got worse with wear.

Now of course my defination of blueprinting may not be the same as whoever prepared this engine you have. I would expect that the crank centerline-to-deck height would have been checked at all points to make sure the deck surface is square with the crank centerline. The crank mains are often (but not always) align bored to make sure all the crank bearings will be in perfect line with each other.

The rods are sometimes checked for center-to-center length and selected to be as close to each other as possible. Everthing that moves is balanced etc.

The list is endless depending how far you go with it and how much of a perfectionist the engineer is. There are not many out there that do not think "that is close enough - the guy will never know the difference."