Finn's new run-up made its debut during the one-day series against New Zealand and he plans to continue with it during the test series, which gets under way in Dunedin tomorrow.
We are only talking about a difference of 5m or so and it is not like it has not been done before. Our own Sir Richard Hadlee slashed the length of his run-up without losing any of his vigour through the crease.
But for a fast bowler to suddenly make changes to his run-up is a big step and Finn was a little uneasy when it was first suggested.
The fact he kept crashing into the stumps during his delivery stride helped him decide to take the idea a little bit more seriously.
''It took me three years to agree to do it, I suppose,'' Finn said.
''It is something I think ... will help me be more consistent, help me get more bounce and help me bowl for longer.
''It is something I've toyed with doing and I've used it in the nets and I haven't had the confidence to use it in a game. But the day before the Napier one-day game, I was in the nets and I said to Sakes [England bowling coach David Saker] `I'm going to do it tomorrow'. He was a bit [taken] aback ... and, thankfully, it worked.
''I still mark both run-ups out just in case but the short run-up seems to be working OK at the moment.''
Finn was initially worried reducing his run-up from about 25m to just under 20m might have an impact on his pace or he might be at more risk of injury by trying to be too explosive through the crease.
''In reality, it is more about the momentum I can gain towards the crease off the shorter run-up, [which] is greater than off the longer run-up, because the temptation is to decelerate at the end of the longer run-up.
''I get better acceleration through the crease. It helps me go straighter through the crease, stand up taller and, hopefully, be more consistent, get more bounce and maintain my pace for longer periods.''
Finn believes he is getting on top of his so-called ''flying knee'' - when he hits the stumps with his leg while delivering the ball.
It happened once in both the one-day and twenty/20 series on this tour, but it came to wider attention during England's home series against South Africa, where it was a persistent problem.
The MCC committee has rubber-stamped law changes that will see a delivery no-balled if the bowler disturbs the stumps while in his delivery stride. That ruling will come into effect in October.
''Hopefully, it won't happen again. It hasn't happened in training ... and it is important that off the shorter run I do maintain the pace, because I think it is the deceleration which makes me get that close to the stumps.''
Plenty of bowlers have disturbed the stumps in their delivery stride with their hand but with Finn, it is his leg. Suddenly, though, the clattering sound is now considered too much of a distraction for the poor batsmen and the laws are set to change.
Finn has not always struck the stumps. He believes he picked up the bad habit while playing domestic cricket in New Zealand for Otago last summer.
Finn and fellow strike bowler James Anderson were rested for the warm-up game against the New Zealand XI in Queenstown last week.
Finn put the time to good use practising in the nets and perfecting the 12 or so strides he now takes to hit the crease these days. Despite that, you might say he does not feel short of a gallop.
