451 Stroker counterweights???

So I've been reading up on building a 451 stroker. I can get a forged 440 crank and 440 rods, pistons I can get off the shelf from KB and the guys at the local machine shop can cut the mains down. My question is do the 440 crank counterweights need to be cut down to rotate in the block without hitting the oil pan rail??? I thought I read somewhere that they do so I asked about it at the machine shop and they said they've never heard of doing that and they clearance the blocks. Anyone know if it's gotta be cut or will it clear???