Blueprinting... Educate the uneducated

I deal with related stuff at work. Any part you design and then send off to a vendor/contractor to be fabricated must have drawings that show target dimensions and EACH ONE needs a tolerance, + or - a certain amount. The wider your tolerances, the less "careful" they need to be when making the part. Some things can be "loose", other parts need to be right on or they won't work properly.

Chrysler was terrible with their manufacturing tolerances. I saw a post somewhere that the allowable range of compression ratios due to "tolerance stacking" (tolerances of various parts adding up once they're assembled together) for a 1968 HP 440 was 9.2-10.1!!! That's atrocious and explains why there was so much variation in performance from the same cars with the same engines. You've heard the stories where one guy's 383 Road Runner stomped everything in town and ran high 13s in the 1/4, then another guy with the exact same car could barely get into the 14s and it ran like garbage. If one had a true compression of 9:1 and the other had 10:1 you can bet it's not gonna perform the same.

I recently had my 440 block bored, honed and decked but not really "blueprinted". To really do that would have required square-decking which is much more expensive and time-consuming. The Icon pistons I got for it all weigh within 2 grams of each other straight out of the box, far better than factory. Haven't checked my 440Source rods yet but they're probably just as good. I also had the crankshaft balanced to the lighter pistons and I'm willing to bet that balance job is now better than it was before with stock-weight pistons. Casting, block machining and rotating assembly balancing were not taken very seriously by Chrysler. By comparison, Buick might have well been Japanese with how much tighter their tolerances were (I'm a closet Buick fanatic lol).