[blykins]

Pistons are available. Cranks are available. All off the shelf.

With increased stroke, rods get longer. You need a 6.250" or 6.300" rod length depending on the counterweights of the crankshaft and the compression height of the piston.

All prices are the same. The cranks are the same price, rods are the same price, pistons are the same price.

The only issue is that with the 4.250" stroke, the pistons start to get pretty short. However, Probe offers some off the shelf pistons that use a 6.250" rod, which helps a little bit.

If you have to have "exactly" 454 cubic inches, then you can do a 4.125" x 4.250". If you can fudge a few cubes either direction, then there a myriad of ways of getting there. People tend to get caught up in the numbers though.