[JLMounce]

I'm starting to accumulate parts for a rebuild on my engine. It's an XJ code 455. It's in good condition, but it was built in the late 90's and has a lot of old era parts, including the factory N crank and factory rods.

It's currently topped with a set of KRE D-ports, as cast and a mild roller cam. For what it is, it runs pretty decent. However the factory rods are a limitation on what I can do with it at this point.

I've had the engine open this past year as some of you may know and everything actually looked great. That's where my question comes in to play. At what point is it necessary to start looking at replacing the factory crankshaft?

The goal with this refresh will be to lighten and strengthen the rotating assembly, while adding some flow to the top end and more cam. Going from the as cast ports to around 290-300cfm or so and something in the 240/250 range on a hydraulic roller...probably something from bullet. Target around 570ish hp with a shift point around 6000 rpm.

The block has 2 bolt caps and is drilled for 4 bolt caps.

This engine is .030 over now and I'm assuming the crank is likely 10/10, but I have no real way to verify that without removal. At the power and rpm levels discussed, assuming the crank checks out, is there even need to spend money on a replacement?

Likewise, what's the need to step up to a 4 bolt cap? I'm leaning towards a simple main stud upgrade. Is that even necessary?

The engine is backed up by a moderately built 4l80e. Has a 3000rpm stall TSP converter with a triple disc lockup clutch. Moser 12 bolt with 3.36's on a TrueTrac. The drivetrain is good to 600whp.

I'm making an assumption the bores will clean up at .040.

I'm just looking at cost savings anywhere that I don't have to spend it, without cutting corners. As a result I'm thinking if I do need a crank, it's likely best to blow past the cast aftermarket stuff and go straight to a forged crank.

Just looking for your thoughts here. This will be the first engine rebuild I undertake.