Excessively large jet sizes may be a sign that your fuel pump is not producing enough volume of fuel to keep the bowls full. The stock \6 fuel pump only produces 19gph which is perfectly adequate for 100hp and maybe a Holley 350.
I don't know of a high flow mechanical fuel pump for a slant 6, do you? I "guess" I could get a big block hv pump and swap the arms out since other then that, they'll interchange. I don't think it's running out of fuel though. It would lay down on hard acceleration draining the float bowls and it's not doing that. At all.