401 overdrive

[p5b401]

Exploring the possibility of installing overdrive for my 401.
As my gearbox is new and diff is in good nick I don't want to modify either of them so an inline unit would seem favourable.
Any thoughts on units which would do the trick?

[Geoff Dowdle]

p5b401,
What is the speed limit where you live??
Do you find you are over revving the engine at your cruising speed ?
Bristol 6 cylinder engines only start to come alive around 70 mph/3500rpm and will cruise all day at those revs or higher .They are not happy chugging along at 2500rpm in 4th gear.
Owners sometimes fit an overdrive to reduce engine revs and noise of a rattly engine and hopefully improve fuel economy .
These owners should spend there hard earned funds rebuilding their engine , reconditioning their worn out carbs and distributor rather than a "Band-Aid " fix of fitting an overdrive.
Most people today are used to driving modern cars that are very quiet , torquey & highly geared (about 1800rpm at 70 mph) giving 45 mpg .

Unless you are often touring between 80 - 90mph I can not see the point of an overdrive.

I fitted a Ford 5 speed Type 9 to one of my 400's which was a time consuming and expensive project . Now after about 3000 miles I'm considering removing it and fitting a Bristol BW CR5 with remote shift (ex 403) which is a better box.

BAC got the diff ratio right for the weight of the car ,characteristics & torque of the engine . It was no accident they would have put a lot of development into it .
The 405 & 406 have overdrive as standard but the diff ratio is lower and engine power and torque is different.

My recommendation is don't bother fitting an overdrive .

Geoff

[p5b401]

Only exploring the possibilities at the moment, haven't driven at speed limits on open roads yet so perhaps sound insulation is another possibility