BBBC Vs BBAB Transmissions

[Colin Thorpe]

Hi,

Can someone give me a quick run though about performance details between my '58 Cabriolet BBBC trans and a '58 BBAB (conv D) transmission.

The first two gears are the same, did the BBAB have a lower top speed?

thanks

[Pat Daily]

Yes--BBAB is lower top speed than BBAC -- everything else being equal.

[Barry Brisco]

Can someone give me a quick run though about performance details between my '58 Cabriolet BBBC trans and a '58 BBAB (conv D) transmission.
The first two gears are the same, did the BBAB have a lower top speed?

Like the Speedster, the D model was considered more of a "sporting" car as opposed to a "touring" car like the Cabriolet model, so it was given upper gears that favored acceleration over top speed.

I found that in my D (with original BBAB gearing) it turned about 200-300rpm higher at highway speeds than my coupe with BBBC. However, I had no problem cruising all day (literally) in the D at 70 - 75mph, the engine didn't overheat even in hot weather. Gas mileage could still exceed 33mpg on the flats.

[Norm Miller]

Colin,

Check the gearing charts in your owners manual or service manual. It will explain RPM to MPH for the different gears.
BBBC will turn ~3000RPM at 60MPH and the BBAB more like 3500 at 60. (off the top of my head).

Norm

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[Steve Proctor]

I can confirm Barry's assertion that you can cruise all day and then some with BBAB gears. Just drove home 13 hours on the road the long way from North Meets South in SLO, CA to Tucson, AZ at about 70 - 75 MPH, 3500 - 4000 RPM. Says a lot for the original horsehair Speedster seats as well.

STP - 60 years old and counting with an iron butt... 8) [/list]