[amallagh]

Thanks for the responses so far giving details of what others have selected for similar but not identical engines.
Main difference to my engine compared to the examples so far I think is they are running milder cams, slightly larger capacity and I guess might have lower compression and maybe not twin plug as it isn't mentioned. I also get the impression that most of the engine mentioned are purely road car engines but I might be wrong.
Votes so far in favour of 40/34s.

I've had a few other comments off line -
- 40/36 may have a reduced venturi effect due to the limited difference in diameters so maybe not the best options for that reason (?)
- Had other comments supporting the view that changing the choke size 34 or 36 hasn't had a lot of effect on their engine which would imply to me that 36 isn't too big and may give slightly more peak end performance.
- One vote off-line for 46s with 36mm chokes on the basis that 36mm venturi are the better size by calculation, and then 46s are better match to this venturi size with a 0.78 ration between them.

I would be realy keen to hear from anyone using 46s in a similar engine who can describe what it is like to drive on part throttle and how it reacts in the mid range, and even what jetting they used.

Also very keen to hear from anyone with some specific advice about the 2 calculation methods described in my first post and their relative applicability given they come out with such distinctly different answers.
Many thanks
Andrew