Your motor if original was one of 1,856 B-body 425 horse 427 engines built in 1967 or 0.0012% of all motors installed; which by definition makes it very rare.
You will need a 5140 forged steel two piece 427 crankshaft. The same stroke forged crank that was offered in the 375 horse 396 will not work. The counter weights are different on the 427 (thicker) to compensate for the heavier bigger bore pistons. The L72 also used 7/16 dimpled rods (hand inspected, and shot peened), not the standard 3/8th inch bolts used on all Passenger BBC engines. The block had four bolts retaining the main caps instead of just two which was standard, and the oil passages were machined for an oil cooler from the factory (only installed on police cars in the case of the B-body).
The problem with this engine and today's gas is that it had 11.0:1 static compression with cast iron heads. That will not work; even with the radical flat tappet race oriented cam that was included with this engine (278ｰ /278ｰ duration at 0.050" valve lift and lift at the valves 0.560"/0.560" on a 108ｰ LSA). If you had aluminum heads this motor was designated as an L88.
You can find a set of used 3873858 date coded A-25-6 here:
You will need new valve springs and rocker studs (ARP sells them) as well as HiPerf long slot stamped steel rocker arms (to handle a high lift cam) with grooved rocker balls (smooth balls were used on std PASS heads). I would run roller rockers instead since no one will see them.
Water pump is the same for any BBC so you can buy a rebuilt replacement any where. If this L72 had been installed in a Corvette it would have had a larger diameter shaft with bigger bearings to support the factory 7,200 RPM red line for this engine (I used to twist my L88's to 7,800).
Carb will be impossible to find. Factory used an 850 4150 Holley double pumper. Every list number for the factory original has been either worn out, or is sitting on top of a L72 under the hood of a Corvette.