Originally Posted by not_a_charger
Thanks everyone.

Oil pressure was checked with a mechanical gauge and confirmed low. Assumption was it was the oil pump, so the plan was to replace the pump when doing the rear main seal. Disassembly found that the bearings are worn. frown

It currently has 10W-30 in it, so making a change there might help me a little.

And Kevin, I'd love to drop a 460 in it, but my understanding is that it's not a direct bolt-in.



You should have just rolled in a set of bearings when you had the pan off it.

If it's a 400M, it should be pretty close to bolt in. A 460 was available in a 250 so if the mounts are different on a 400M, the correct ones should be readily available.

Kevin