[flat-bill]

You should watch out for the first gear ratio on at least some of the TKO500's. Some of them have a really deep first gear ratio.

TREMEC
Part Number Weight
(lbs) Torque Cap.
(lbs-ft) Gear Ratio Chart
1st 2nd 3rd 4th 5th Rev
TCET5201 105 500 3.27 1.97 1.34 1.00 0.68 3.00
TCET4615 105 500 3.27 1.97 1.34 1.00 0.68 3.00
TCET4616 105 500 3.27 1.97 1.34 1.00 0.68 3.00
TCET4617 105 600 2.87 1.89 1.28 1.00 0.82 2.56
TCET4618 105 600 2.87 1.89 1.28 1.00 0.82 2.56
TCET5008 105 600 2.87 1.89 1.28 1.00 0.64 2.56
TCET5009 105 600 2.87 1.89 1.28 1.00 0.64 2.56

A 3.27 first gear is not going to be very useful except with a very high rear axle ratio. Then the OD becomes useful only at about 90.

[tom s]

I have the 3.27 first with my 69 firebird and a 3.36 rear.I really have no issue with it.When I had the 3.90 it was just too low.The .67 OD is perfect for my combo.I have the 600 in my 421 Lemans with a 3.90 and it is fine.Tom

[tom s]

Should have said .68.My 600 has the .64.Tom

[crazycarlo]

So did you ever figure this out? I'm also curious about a 5 speed in a pontiac.

[Overkillphil]

What were the issues with the Doug Nash trans that prompted the desire for change?

[Formulajones]

My guess would be he just wants more overdrive.

Even the nash, when running a 2.73 rear gear, still doesn't give you the final drive ratios that say....a .64 overdrive with 3.42's will provide. You could even step up to 3.73's or even 4.10's with a .64 and still have more overdrive (final) than a nash/2.73 setup.

Couple that with parts availability, and the Nash has kind of fallen out of popularity.

I have a T56 in one with .50 overdrive. You can run a pretty ridiculous gear in it and still have comfy highway cruising.