Question re BWCR12 non overdrive gearbox as fitted to AC Ace Bristol

[Glen Smytheman]

Hi all,

I had a spare Ace Bristol non overdrive gearbox that we have fitted to an early Type 401 Bristol saloon.  In test drives the car goes very well (spare BS head has also been fitted that would have raced in the New Zealand Grand Prix back in the 1950's that my dad had under the bench in garage for the last 40 years) but is a bit of a challenge to get underway due to gearing.

My questions are therefore is anyone able to tell me:
1.   The gear ratios for the gears as fitted to a standard BWCR12 gearbox
2.   The Bristol part numbers for each of the gears fitted to a BWCR12 gearbox.
3.   Whether the gears are interchangeable from a Bristol saloon 403 gearbox (BWCR5) into a BWCR12 gearbox

Many thanks

Glen Smytheman