2 general questions

[Stegs]

1. My car came with the clock in the dash, Its not working at this moment. I honestly don't need a clock and want to replace it with a B body factory tach that will fit? is this just as simple as removing the clock, and adding the tach....also will it run off my firecore distributor?

2. my speedo is 10 mph fast. If the speedo says 60 mph, by gps im really only going 50? how would I go about fixing this so its closer to the correct mph?

[lukedukem]

1. My car came with the clock in the dash, Its not working at this moment. I honestly don't need a clock and want to replace it with a B body factory tach that will fit? is this just as simple as removing the clock, and adding the tach....also will it run off my firecore distributor?

yes it should. mine was the same, i do not have a firecore distributor but the wire runs to the +side no matter what coil.

2. my speedo is 10 mph fast. If the speedo says 60 mph, by gps im really only going 60? how would I go about fixing this so its closer to the correct mph?

do you mean gps is showing 50mph. is so, then you need to change the gear in the tranny. my car also read 10 over what its going. my car has a 3.23 rear and it was a small block tranny, now its a big block and i need to change the gear in it to match.

luke

[Stegs]

great, thanks for the info


Yes the speedo always reads 10 mph faster than what im actually going. My trans is a 727HD from a BB car (383)

where would I find the part I need and where is it on the trans? is this something you can get to by crawling underneath or should the car be up on a lift?

I believe I too have the 3.23 gears with a suregrip

[Ghoste]

There are a variety of speedo drive pinions, you need to know your tire diameter as well, there are charts you can use to determine the pinion you need and you may be able to order it at your Dodge dealer.  It is located on the left side of the trans on the forward portion of the tailshaft housing.  Do you have a factory shop manual?

[Stegs]

There are a variety of speedo drive pinions, you need to know your tire diameter as well, there are charts you can use to determine the pinion you need and you may be able to order it at your Dodge dealer.  It is located on the left side of the trans on the forward portion of the tailshaft housing.  Do you have a factory shop manual?

no I don't, im hoping my wife gets me one for my birthday.....

Im ok with it now being off, as long as I know that its 10 mph faster, I can live with it....I was just curious if its a easy thing to replace (easy to get to)

I will get my tire height and see if I can find that chart

thanks guys!

[John_Kunkel]

Before you go changing speedo pinions, compare the odometer reading to a known surface distance...in many cases the odometer will be right on or very close while the speedo is way off and only speedo head repair can fix that.

Always use the odometer to determine if the correct speedo pinion is installed.

[Kern Dog]

The speedometer cable screws into the left side of the transmission. Unscrew the cable and you'll see the housing that contains the speedometer pinion/gear. There should be a horseshoe shaped flat steel retainer held in place with a 1/2" hex bolt. Remove the bolt and retainer and pull the housing from the transmission case. The speedo pinion will fall right out.
There are charts online that will help determine which pinion that you need. You need to know the rear axle ratio and rear tire size. Often times, one tooth equals 2-3 mph. Example: A 29 tooth pinion reading 10 mph fast should be replaced with a BIGGER pinion that slows down the speedometer guage, maybe something like a 32 or 33 tooth.

[Stegs]

The speedometer cable screws into the left side of the transmission. Unscrew the cable and you'll see the housing that contains the speedometer pinion/gear. There should be a horseshoe shaped flat steel retainer held in place with a 1/2" hex bolt. Remove the bolt and retainer and pull the housing from the transmission case. The speedo pinion will fall right out.
There are charts online that will help determine which pinion that you need. You need to know the rear axle ratio and rear tire size. Often times, one tooth equals 2-3 mph. Example: A 29 tooth pinion reading 10 mph fast should be replaced with a BIGGER pinion that slows down the speedometer guage, maybe something like a 32 or 33 tooth.

I was told its a 3.23 gear suregrip.....tire size I can look when I get home.....