These blocks don't have a vtec oil channel. And the pistons don't have the wright design for lean eco driving

I want to make a car that is fun but also fuel effecient. So I was brainstorming to make a 3stage vtec with a destroked d14block with a d12 of d13 crank and small turbo. I was wondering if the bearings are the same. And wath is the rodlength of a d12? And how mutch can I mill the head en bock to get...