The big truck L6 SV series (306, 331, 377, 413") have large bore pitch, but staggered differently from most many older engines into front and rear halves.
Cylinders #1-2, 2-3, 4-5 & 5-6 are 4.750” apart (same as modern Buick V8), but cylinders 3-4 are 5.5625” apart with a huge center main bulkhead.
