Posted by George on January 11, 1999 at 05:23:14:
In Reply to: Are 4.89 gears worthwhile? posted by David Hogan on January 09, 1999 at 12:00:23:
I put 4.89s in my 56. These make for less frantic
highway travel, but it is misleading to think that
your road speed will scale up in direct proportion
to the change in ratios. In principle yes, but in
fact, the flatheads (230s at least) have their hands
full trying to move these trucks at an honest 50-55
on a flat road. I still drive mine about 50-52, like
I did when it had 5.89s, but now it runs at about
2500 rpm instead of 3000 or bit more. It no longer
sounds like it is going to come apart.
It does start up fine in 2nd gear...some people had
warned that you would need to start in 1st.
The gearing can be a bit awkward at city speeds. There
is a big gap between 3rd and 4th. I have a little
hill where I am and it can't pull it in 4th because
the rpm is about 1200 but keeping it in 3rd means
it runs out of rpm before you can get a decent road
speed. In this particular case, it would pull the
hill in 4th with 5.83s. These trucks really need
a five speed trans!
All things considered, I do prefer the 4.89s if you
do any highway driving like I do to shows etc. I don't
think I would both to change the gears if it was
mostly used off road or at city speeds. And as has
been noted, you can't really combine these gears with
bigger tires...the 4.89 gearing with standard size
tires is at the limit for the 230. I have a feeling
this combination would be a lot better with the
251 engines but I haven't tried that. I do have a
251 with standard gearing and in my view, the 251s
are just enough more powerful to make a noticeable
difference.