A few 4.56 gears Qs.

From: Bob Tom (tigers@bserv.com)
Date: Thu Oct 17 2002 - 09:50:48 EDT


Hi

At the track, I am currently running with 3.92 gears, 26" drag tires
44RE auto. and a 3000 (flash) stall converter with a total race weight
of 4,080 lb. Prior to my diy ported heads, a dyno. showed that my
peak hp was 5000 rpm. With my current setup, I'm going through the
traps at around 5000 rpm or so.

I will be getting another dyno. at the end of this track season but
I suspect that the ported heads may have moved the peak hp up
to about 5300 rpms. I'm replacing the R/T cam over the winter
and I suspect that the replacement cam will put my peak hp rpm
in the 5600 to 5700 rpm range.

Because the 4.30 gears are no longer made for the 8.25" rearend,
my only option is to look at the 4.56 gears (I may have to go with
28" drag tires) to get me through the traps at 5600 rpms or so.

Is there anyone out there running with 4.56 gears (preferably in
a 4x2 and 8.25")?

How are the 4.56 gears in street and highway driving? I know the
OD is a great compensator for low gears but is it enough for 4.56s?
I'm old enough to have owned and driven mopar muscle cars in 70
and 71 to be comfortable with 3000 rpm at 70 mph. My street tires
are 28"ers.

I've seen conflicting messages that putting 4.56 gears in the 8.25"
may require some internal modding in the carrier (something to do
with the rear abs?) I've looked at some sites and have not been able
to confirm or not confirm this. Has anyone had to do this?

Thanks for any inputs and/or suggestions.

ticats



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