I always wonder about 302/351 builds being more expensive. The machine work cost the same. Forged pistons should be about the same. stroker crank will cost a bit more. Heads the same, balancing will cost the same,bearings ,rings should be close, maybe a bit more on the bearings for the 51. Ign should be the same, headers should be a bit more. Although at Crites a set for the 351 were only 350. The arp bolts will be a bit more because of the different size. Overall should not be more than 10/15 percent, but what a bang for the buck. Putting a 351 w block in a early falcon/comet/mustang only requires a 3/4'' block on top of the m/m. have made the swap many times. Again there will be as many ways to build as there are builders.