1966 Series 5 rear end

[Jim in PA]

Hi again...I am still learning loads of stuff every day from so many of you. Thanks.
Now I'd like to ask about the rear differential in my 1966 S5. No OD.
I'd like to have rear end gears that are more "geared" to cruising than drag racing. The ratio now is 4.10 or so to 1. I'd like to have closer to 3.07 or 3.08 for better top end speed without the high revs. Even 3.3:1 would be an improvement. I'll take what I can get.
Where do I find the gear set? What tips can you share. I'd need to crawl under the Alpine and get numbers off of the unit but so many of you know this stuff right off the top of your head.
What markings do I look for on the original unit?

 

[RootesRacer]

With the stock rear, you have 3 choices.

1) 4.22 which is probably what you have in the car.
2) 3.89 which is probably what ought to be in the car.
3) 3.70 which is what would be nice to have in the car.

3.70 is the gearset that was used on the arrow series alpines, not available
on the series alpines, but it does fit.

New 3.70 gearsets are available from rootes spares.

 

[Rodewaryer]

I have no idea why, but my Series 5 came to me without OD and had 4:22 rear. Redlined at about 95mph and made me very unhappy. It's now a 3:89 with OD. Very nice cruising and yet not too high geared.

 

[RootesRacer]

I have no idea why, but my Series 5 came to me without OD and had 4:22 rear. Redlined at about 95mph and made me very unhappy. It's now a 3:89 with OD. Very nice cruising and yet not too high geared.

Most SVs seemed to come from the factory with 4.22 with or without OD.

 

[jumpinjan]

They all came with 4.22 and with the new 1725 engine, they were trying to keep up with all the muscle-car mania.
Every series V owner needs to get rid of that 4.22 gear.

 

[Rodewaryer]

Oh, so I wasn't alone in my pain.



But no more.

 

[George Coleman]

The 3.70 gear is the way to go!! If you feel froggy match it up to a Toyota 5 speed, I like mine I can cruise at 72mph at 3500 rpm or 60mph on country roads at 2800rpm, anyway you can not go wrong with the 3.70 gear

 

[alpine_64]

They all came with 4.22 and with the new 1725 engine, they were trying to keep up with all the muscle-car mania.
Every series V owner needs to get rid of that 4.22 gear.

Jan are you reffering to the USA delivered cars?.. i though that was a state side thing. I think HRO home market cars still had 3.889's in them without OD.. or at least quite a few did.