Contemplated Milodon 4 bolt caps when doing engine. They are available for the 351W.
Most factory heavy duty truck, marine, and hipo automotive engines have 4 bolt mains on center 3 caps.
Two schools of thought for retrofit. The factory 4 bolts were anticipated to see a lot of strip and track use. If you anticipate strip, track, supercharged street, nitrous street, then retrofit 4 bolt mains along with aftermarket forged rods, and pistons.
If this is mostly street with a burnout from time to time, most of this bottom end beefing is a waste of money. Use ARP studs and the 2 bolt caps are fine. The stock crank is fine. The stock rods, provided they have been reworked for hipo street use are fine. hypereutectic KB pistons are fine.
However, a windage tray, and a baffled style Road Race
oil pan is a good investment for a Cobra motor. Cobras, even street only Cobras experience more violent acceleration, decelleration, and cornering and need positive
oil control.