the difference between a 2117 crossbow bolt and a 2216 crossbow is 99
Chrome plated is using electric plating method to have a layer of chrome plated on top of the metal, (usually iron or steel. ) because of the nature of the chrome it will prevent rusting of the surface of the metal.Stainless steel is an alloy containing chrome and aluminum and many other traceable amount of metals, different grade of stainless has different ratio of contains and give different characteristics to the steel.
you can identify the slight different between an imperial bolt and a metric bolt by looking how fine their thread pitch looks like or feels like
Caliber, where made, bolt
.5 inches
a grade 8 bolt is stronger, about twice as strong.
NPT = pipe Briggs standard = Pipe NFT and NFC and ASAE = bolt
http://holdenpaedia.oldholden.com/Block_Patterns
There is really no difference between the two. Although it seems common practice that the plummer blocks are split, with bolt on caps.
One uses 3 bolts to mount it, the other 6
100-500 USD
The difference between a 2 bolt main and 4 bolt main is how many bolts hold the caps that hold on the crankshaft. (A 2 bolt main has 2 bolts to every cap and the 4 bolt main has 4 bolts to every cap) A 2 bolt main should be able to handle 500hp as long as you don't push it above 5500RPMs.