Rich wrote,
> I always felt the the stock 3.89:1 rear ends were to low to
>begin with, and going even lower to 4.55:1 would keep if off the
>freeways forever. I always felt that the perfect ratio was around
>3.24:1 The Tigers 2.88 would have been too high. The 73' Datsun 510
>wagon rear end that I bought for my conversion project had 3.24. I was
>told that it used the same gear set as the 240 - 260 Z's. I figureed
it
>would be tough enough.
>
> 4.55 will wind it up tight at 70 on those country freeway miles.
>
>
>Richard
Well then, the only Rootes/Chryslor rear that will be suitible for you
would be
the 3.70. The gears will get no taller than that.
A 3.89 equiped alpine will run at about 3450 RPM at 60 mph. This is a
reasonable
RPM, considering the little motor "yes even a stock one" will make peak
torque
at 3800 RPM.
a 4.55 rear puts you at about 4050 RPM at 60, so unless you really like
to rev
your motor, you'd best have an overdrive.
Acceleration comes at the expence of more gears or lower top speed.
With a 3.70, the 60 MPH RPM will be about 3280, so the amount of RPM
drop
is not too drastic, nor will be the slight loss of torque.
If you want to use a a lower numerical ratio yet, I dont think I would
go too much
lower than 3.70 because the motor will be running "outside the cam", and
too
much load can burn up those teeny tiny alpine exhaust valves.
Iffen you are going to put a torquey V8 in there, then thats a horse of
another
color.
Good luck!
Jarrid Gross
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