Hiya Lin - Phoenix - good to see you here.
If you do go ahead & take max in this - Al says if Nige is busy, he'll come & 'crew' for you!
Costs? I have blatantly copied over part of a response to one of Tims enquiries:
First, comparative dyno runs for the 600 and 620 engines:
(620 red, 600 green, both running standard airbox and filter and race cans)
Couldnt copy graph... sorry
but...
From that it would seem that you really want to be on a 620, rather than a 600. Differences include longer crank throw, same bore, main advantage comes from much bigger inlet and exhaust valves, shorter inlet tracts and larger throttle bodies means it breathes much much better, which will translate to a large performance advantage. And electronically managed fuel injection of course. The 5.9 ECU is fairly tolerant of tuning mods so you may get away without the power commander.
As for budget, I would say realistically to buy and race mod a cheap 620 and run it over the six race series, you're looking at £5 - £6K minimum. You will need to rework the front fork internals, the rear shock needs beefing up to be competitive, open airbox and performance filter, hi level race cans, rearsets, clipons, two sets of rennsports at £200 a set, and if it's wet you'll need a pair of race wets as well, another £200+, ideally fitted to spare wheels so you can swap quickly on showery days. You'll need to fabricate a 4 litre catch tray under the engine to comply with regs as well. Add the £800 entry fees, you're at £6k already, and you may want a race van / caravan, generator, tyre warmers etc yet. Of course you can do without some of these things (i regard the genny and tyre warmers as a luxury for instance) but without the suspension and performance mods you'll be struggling from the off, particularly with circuits like Cadwell and Donnington in the line up.
Bit of a discussion going on there about it now - maybe you might get some new members Lizzie?
C