No no no! The thinking is understandable but it doesn't work like that at all. If you set out too fast, you'll crash and burn early. It'll hurt, you'll be miserable, and most likely you'll end up finishing much later than if you'd set out slow and steady right from the start.
My first ultra, I was rather worried about the pacing so deliberately set off at the back of the pack (so I wouldn't be tempted to try and keep up with faster runners) and very carefully bimbled along about a minute per mile slower than my marathon pace. It felt ludicrously slow but apart from a rather bad two mile section between miles 21 and 23, I kept going at a steady pace till 30 miles, when I realised I was still full of puff and thrashed out the last 3 miles at a fair old gallop. Felt great being able to overtake folk that were walking!
Compare that with a recent marathon outing where I felt great at the start and foolishly set off at an unsustainable pace, kidding myself on that I might be able to keep it up till the finish. I started slowing down at the halfway point and from 17 miles was just jiggered. The last few miles were a rather ignominious shuffle-stagger...