what rear axle ratio???

[scarface]

hi guys.im installing a modified ford 460 big block and T56 6sp trans into my cobra.i have the prop to go to a jag rear axle but need to know what ratio (gearing) would be best for it and which car would have it in.
Its mostly for straight line racing but still needs to be driveable on the road.
any help would be greatly appreciated.
thanks again

steve

[TINKA]

There are 2 main options either a 3.31 or 3.54, as you are fitting a 6 speed box, you would probably be best off with the 3.54. IMHO hope that helps

[scarface]

cheers mate.someone else also recomended a 3.54 so i think that will be best.

thanks again

steve

[Antony]

I think it depends on what is available for your differential, I would be
looking at either 3.73, or if they make a 4.10, as I am looking at fitting a
T56 with racing 374 cuin Nascar engine, 4.10 ratio 7000rpms = 180mph approx, this
this will give a good acceleration, but my T56 will have a 0.75 sixth gear,
this also gives about 2350rpm at 60mph or about 3000rpm at 80mph.

You may want to use a 3.73 ratio and my car is on 25.6" diameter rubber,
and that will give you approx 2150rpm at 60mph. Best thing to do is
use a calculator, here is web link to a good graph type gear ratio!
I personally think having a 0.62, 0.50 sixth gear as ridiculous unless you
have a big block which only revs to about 5500rpm or less!

http://www.geocities.com/z_design_st...ion_z28_6.html

[TINKA]

Originally Posted by Antony

I think it depends on what is available for your differential, I would be
looking at either 3.73, or if they make a 4.10, as I am looking at fitting a
T56 with racing 374 cuin Nascar engine, 4.10 ratio 7000rpms = 180mph approx, this
this will give a good acceleration, but my T56 will have a 0.75 sixth gear,
this also gives about 2350rpm at 60mph or about 3000rpm at 80mph.

You may want to use a 3.73 ratio and my car is on 25.6" diameter rubber,
and that will give you approx 2150rpm at 60mph. Best thing to do is
use a calculator, here is web link to a good graph type gear ratio!
I personally think having a 0.62, 0.50 sixth gear as ridiculous unless you
have a big block which only revs to about 5500rpm or less!

http://www.geocities.com/z_design_st...ion_z28_6.html

Hi Antony, sorry to say that those ratios you mention are not available in the form of XJ6 rear diffs, now if it was a xj40 that would be a different story as they come in a wide variety of ratios

[v8robert]

Originally Posted by TINKA

Hi Antony, sorry to say that those ratios you mention are not available in the form of XJ6 rear diffs, now if it was a xj40 that would be a different story as they come in a wide variety of ratios

Clever clogs !

[mylesdw]

Originally Posted by TINKA

Hi Antony, sorry to say that those ratios you mention are not available in the form of XJ6 rear diffs, now if it was a xj40 that would be a different story as they come in a wide variety of ratios

I may be wrong, and I don't have the book handy but I thought that XJ6 diffs were available in these ratios. Probably not with a powr-lok granted but the early 2.8 autos came with quite low ratios. I'll try and remember to look it up...

[gwak76]

Range off diffs attached, they come in some strange old ratios, I have a 3.77Pl in the garage for some reason.