In am swapping a 350 chevy that has been bored .040 into my 85 Z28.

I was just looking for some opinions as to what types of oil and spark plugs people use with a 350 setup and what type of impact it can have.

I was thinking of using Amsoil either 10w30 or 10w40 weight. What difference would one make over the other?

What is the difference between Platinum and Iridium tipped spark plugs and what are some good brands to go with?

Thanks.

Denso Iridium

NGK iridium