<VV> 3.08 gear experiences

[craig nicol]

Mike said:

<snip>I've been very satisfied w/ my Rampside 95HP and PG using 3.55 here in
the hills and mountains of SW Colorado. Does anyone have any experience w/
3.08's in any car or trans combination? I don't ever remember even seeing
them. Were they available w/ any transmission? <unsnip>

 

Craig replies:

Originally, they were only available for a short while in early '63. I don't
know why they were pulled from the offerings. Some have speculated that they
were only produced to permit them to be used in the Mobil Economy Run.  I
suspect the growing performance market and/or the tiny '63 three-fin oil
coolers were bigger factors.  Based on my experience with a friend's '63
that had them from the factory, I saw nothing to not like about how they
performed.

 

Currently, I have two LM cars with 3.08 gears - mine are the reproduction
gearsets that are drilled for either six or nine bolt carriers.

 

Car #1 EFI 140 with late FC-type (3.65 first) transmission.  This car has
the 304 cam and although first gear takes off very well, at cruise the rpm
is a little low for the cam and the result is OK but not awesome.  . Now if
I'm cruising at 80, she's really peppy.

 

Car #2 Hi-torque 140 with early car trans (also 3.65:1 first).  This engine
has the retarded 889 cam that was originally for PG 140s.  Now this combo
really is the cat's meow. It does everything right and is the way GM should
have sold these cars.  Strong from a stop, strong mid range, strong pull at
cruise.  It really has some punch when the secondaries come in too 'cause
that's right where the cam is happy.  

 

There are two keys to the combo:

Proper overall first gear (trans 1st x axle ratio) over 11:1

A camshaft profile that makes lots of torque at cruising speeds

 

That's my story and I'm sticking to it!

Craig Nicol