My understanding of dnyo's is that they work out RWHP using the torque figure etc.... then work out flywheel power by calculating how long the rollers stay running for.when they take their foot of the gass.... my thinking is that a nice tight transmission will offer a lot of resistence to the rollers and slow them down quickly, a rubbish transmission will offer very little resistence and they'll keep spinning for ages.
Please bear in mind that I just pulled that theory out of my arse
Tdraper, my car was dyno'd at Engine Advantages in Witham, on the industrial estate just behind Ford rapid fit (suberb guys btw)
p.s., Gordon, my engine was (and is) totally stock when it was dyno'd.... stil had the original 112mph limiter installed, but how accurate the figures are I don't know (somehow made 336lb torque )