Anyway Mr Bush. What is it like with a 3.94Fd ad I want to do that to mine?
Seeing as you asked so nicely

I'm a bit 50/50 on it atm I had the box rebuilt last autumn after a diff explosion.
Its good in the sense that I am faster off the mark and feels like 20 bhp with the fly but the 8v runs out of puff at just under 6k.
Its great up to the point the 8v hits the limit when the car starts to feel like its kangerooing, you can only polish a turd so much

The daily commute is driving around in second and therefore very annoying.
I would expect an extra 8 valves would be a slightly better scenario as the extra low down pick up would be a benefit and would not lose out too much in the top end trade off.
I do like the extra pep i get in the country lanes, with 8 more valves this could be more fun