what diff ratio

CastleMGBV8 · Post by **CastleMGBV8** » Mon Dec 01, 2008 9:43 pm

Tom,

If you use the 215/55 x 17 tyre with a 3.62 diff that gives you a 40MPH 1st gear and an economical cruise 70MPH at around 2650RPM.

Kevin.

BadgerV8 · Post by **BadgerV8** » Tue Dec 23, 2008 7:50 pm

Tom

I use a 3.36 ford diff in my little kit car with an LT77, on a little bigger diameter wheels, and that seems about right for motorway cruising. I'd guess the '5 is probably has a bit less drag... ?
I used to have a 3.62 ratio and found it a bit high. So the calculator sounds about right to me.

Dave

mgbv8 · Post by **mgbv8** » Tue Dec 23, 2008 8:04 pm

Kev!
My old MGBV8 3500 setup was 257bhp and topped out at 147mph. I had to give up then as I couldnt hear the pace car on the phone over the wind noise!!!
Plus the fact that I was filling my pants at that point.

Paul B · Post by **Paul B** » Wed Dec 24, 2008 2:00 pm

My RV8 Morris hot rod had a GM180 autobox and 3.9:1 Sherpa rear end, and 28" tall tyres, and it revved its taters off, a tad over 4000 rpm at 80mph. It accelerated like a very fast thing, but it got a bit tedious revving so high on the motorway. It always felt like it needed a 4th gear.

With that gearing I'd be lucky to get 110mph before the motor threw bits out at me.

Now a screaming four banger would be laughing with that gearing, but not a rumbly old stock 3.5 V8.

My new project has a 3.5:1 Westminster rear end, and a big Ford V8, so the revs will be a bit better, but I fear still a bit high.

topcatcustom · Post by **topcatcustom** » Wed Dec 24, 2008 4:58 pm

I'm going to find and fit a 3.62 to start with- it shouldnt be far off and that will give me a good starting point. Thanks for the info though

mgbv8 · Post by **mgbv8** » Wed Dec 24, 2008 6:40 pm

Paul!!
The Westminster axle is the Salisbury axle isnt it??
Same as My MGB V8 axle....But the stock MGBV8 diff is 3.07:1

Paul B · Post by **Paul B** » Thu Dec 25, 2008 8:15 pm

mgbv8 wrote:Paul!!
The Westminster axle is the Salisbury axle isnt it??
Same as My MGB V8 axle....But the stock MGBV8 diff is 3.07:1

Not to sure if it is the same, but I believe the diffs are interchangeable; and I've also heard the Westy ally diff housings are much sought after by MG racing boys, to save weight.

It is interesting to know that 3.07 gears might be available, should I find the one I have to revvy.

I put a Westy diff into my Sherpa housing on the Morris, and it fit perfectly . The spline was different on the half shafts, so I swapped the Sherpa spider gears into the Westy diff, after removing a couple of shims.

Does this housing shape look familiar?