400 4bolt or 2bolt

[kanuck]

Not that I was looking for them, but I ended up with 2 400 SB engines.
The first is a 74-77 approx 2 bolt short block with standard bore in need of a rebuild ($50). The second is a 70-73 4 bolt short block also in standard bore ($100).
Looking at the valley of the 4 bolt block it has the heavier casting, as pointed out to me by an engine builder, of the high nickel early blocks. (Have a 1970 350 4 bolt from a heavy tow truck with the same casting).
Wondering which to build as a street motor and which to keep for a more street/strip. I was told in the 400 SB that the 2 bolt was stronger than the 4 bolt unlike in the 350 SB.

I ended up finding 2 sets of hyperutectic pistons at our last swap meet, both for .30 over 400 sbc. Both sets of pistons are flat top with the 4 valve reliefs, but one set uses stock 400 rods and the other uses the longer 5.7inch 350 rods and has the anti-friction coating on the skirts. Both sets of pistons are like new and have no more than 1000 miles on them.
Would like to use the ones with the 400 rods for the street motor and upgrade the other set to H beam 350 pistons for the street/strip.

So opinions on which block to use??

Thanks