When you build combos with higher cubic inches there are so many ways to get where you are going. My 572 combo I put together in 2009 had a set of Indy pistons cut for 440-1 heads. I then had them cut for B1’s also. It had a stock length 440 rod in it. The 572 I am building now has a 7.150 rod in it. I see lots of used pistons out there but you won’t find many on the shelf. It doesn’t take that long to get a set of custom pistons made