need your help for my bristol 411

[jochen]

hi everybody,
my name is jochen and I do not own a A body car, but a rare british classic called Bristol 411 series 1. I seek help from you guys, because this 1970 Bristol is standard equipped with a 383 mopar engine and a 727 trans. I live in germany and as you know we do not have speed limits on our highways. This means, that the gearing problems of older cars, of which you suffer on your highways at say 70 mph, are even more severe here, often cruising at 100mph.
I looking for ways to reduce the rpms at those speeds, and so far, the car has been modified with a 2,88 final ratio (standard is 3,07) and 205/80/15 tires (standard is 185/80/15)
This helps of course, but I am looking now at the Gearvendor overdrive, which you probably all know. My problem is, nobody overhere is familiar with this, even in the bristol owners club no one has any experience. Thats why I would appreciate any help from you guys!
My questions: would a Gearvendor OD make any sense at all with the 2,88 final ratio, or would that reduce the rpm's too much (i.e 1600 rpm at 80 miles!?) How would the gear vendor work in auto mode under these conditions, i.e. cutting in and out all the time because of too low torque at these low revs? So would only a manual operational mode be possible? And what about the (standard) converter in the 727, would that start slipping and therefore be very inefficient? Anyone who has an idea about this is very welcome to give his opinion and I thank you all much in advance!And: Happy 2015! Regards, Jochen

 

[Abodybomber]

hi everybody,
my name is jochen and I do not own a A body car, but a rare british classic called Bristol 411 series 1. I seek help from you guys, because this 1970 Bristol is standard equipped with a 383 mopar engine and a 727 trans. I live in germany and as you know we do not have speed limits on our highways. This means, that the gearing problems of older cars, of which you suffer on your highways at say 70 mph, are even more severe here, often cruising at 100mph.
I looking for ways to reduce the rpms at those speeds, and so far, the car has been modified with a 2,88 final ratio (standard is 3,07) and 205/80/15 tires (standard is 185/80/15)
This helps of course, but I am looking now at the Gearvendor overdrive, which you probably all know. My problem is, nobody overhere is familiar with this, even in the bristol owners club no one has any experience. Thats why I would appreciate any help from you guys!
My questions: would a Gearvendor OD make any sense at all with the 2,88 final ratio, or would that reduce the rpm's too much (i.e 1600 rpm at 80 miles!?) How would the gear vendor work in auto mode under these conditions, i.e. cutting in and out all the time because of too low torque at these low revs? So would only a manual operational mode be possible? And what about the (standard) converter in the 727, would that start slipping and therefore be very inefficient? Anyone who has an idea about this is very welcome to give his opinion and I thank you all much in advance!And: Happy 2015! Regards, Jochen

Welcome, and very cool car Jochen. ( 1 of 287 , is kind of rare...). Let's start, with a few questions. What rpm/ speed would you like to drive at ? Is thr 383 still stock, or have you added a bigger camshaft ? This would be questions, to a minimum. If a moderator reads this : Any chance this could be moved , to the drive train forum ? If so, much appreciated in advance.

 

[Abodybomber]

Have you tried, some of the European Jensen Interceptor websites ? Same basic drivetrain, same situation....

 

[jochen]

Welcome, and very cool car Jochen. ( 1 of 287 , is kind of rare...). Let's start, with a few questions. What rpm/ speed would you like to drive at ? Is thr 383 still stock, or have you added a bigger camshaft ? This would be questions, to a minimum. If a moderator reads this : Any chance this could be moved , to the drive train forum ? If so, much appreciated in advance.

Thanks for your reply. Yes the car is rare, and the series 1 version it is even rarer, only about 65 build.... To your questions: the 383 engine is stock except for balancing, headers and the msd atomic EfI. In top gear I would like to drive with as low as possible rpm, and that is
Exactly what my question is about: how low is too low for the engine? It would be nice if the Rams in top gear would feel comfortable for the engine from say, 75 miles upwards and make traveling with 100 mph comfortable for the drivers ears and his gasoline wallet....
Again: the final ratio is already lower than stock 2,88, the tires are 205 instead of 185/15 so there must be a limit going further down? And: as far as know the OD in auto mode will cut in automatically from around 47 mph so that might become a problem because of too low engine revs? Thanks in advance for your time and effort to help. Regards, jochen

 

[66fs]

The 383 is a high torque engine, even the factory High Performance engine. It sounds like the Overdrive speed is programmable. I have a 1968 383 727 Formula S Barracuda that was basically stock High Performance that I drove as a daily driver for years. I used to swap 2.76 gears with 235 60 14 tires in for long trips. It never slowed down much going up hills. As long as you have the money and it physically fits it sounds like a great way to go. The top speed would also be amazing.

http://www.gearvendors.com/hrdodge3s.html

http://bristol411.co.uk/

 

[360duster]

Hi Jochen,

i don´t know this Bristol....but i know that there are several mopars here in Germany equipped with the GV overdrive. I´m sure you can get very good info here at fabo, but at the german mopar forum also. the moparshop is a dealer for GV over here, they installed some of these units......maybe you give them a call.

Michael