66 Impala Tachometer Identification

[SuperNovaSS]

I was wondering if anyone can help me with identifying this tach. It was found in a defaulted storage locker that as sold at auction. It is a 66 fullsize Chevrolet tach for the L72 427/425HP. The 427/425HP engine could come with a points or Transistorized ignition system. I believe the points and TI system used a different tach. I would like to know whether this tach is for transistorized ignition, points, or both. The GM part number is on the back but the last number is very hard to make out. The first 6 numbers are definitely 641254. The last number looks like it could be a 3 or a 9 but could also be something else. Can anyone help?


Thanks,

Jason

[SuperNovaSS]

Nevermind, I found this with a little Google searching:

Here's the break-down on 1966 tachometers:
6412548 - 6000 rpm, 5k red line, used with 283/195hp, 283/220hp, 327/275hp,
396/325hp
6412571 - 6000 rpm, 5k red line, used with 396/325hp equipped with RPO K66
Transistor Ignition
6412983 - 7000 rpm, 5500 red line, used with 427/390hp
6412572 - 7000 rpm, 6k red line, used with 427/425hp equipped with RPO K66
Transistor Ignition and also 427/390hp with RPO K66, 1st design
6412984 - 7000 rpm, 5500 red line, used with 427/390hp equipped with RPO K66
Transistor Ignition, 2nd design
6412549 - 7000 rpm, 6k red line, used with 427/425hp


It must be 6412549. Now I have to decide if I want to risk dipping the face in evaporust :-)




Thanks,


Jason

[olredalert]

----Rare piece, Jason......Bill S

[SuperNovaSS]

Thanks Bill,

It was really weird, there was a bunch of Buick Skylark and Harley parts in the storage locker but this it the only Impala piece I have found. I'm finishing cleaning out out today. Hopefully the engine is in the back corner!



Jason

[mssl72]

Find that on Chevytalk??

[SuperNovaSS]

Mark,

I didn't find it there originally. It was some sort of PDF file that looked like it was originally an email answer to someone kinda weird. After I knew the correct part number I found your post which looked very similar to the original one I found.


Thanks,

Jason

[SuperNovaSS]

Well, multiple people told me not to try to clean the tach face. After thinking to myself, "What would NJSteve do?", I took that as a challenge and went for it. I tested the gas gauge first by dusting it off and spraying it with Windex. When the numbers didn't wipe off or smear, I figured it was worth the risk to take the tach face off and dunk it in the Evaporust.



Here is the tach face removed and placed in a Pyrex dish so I could periodically heat the liquid on the stove(it works much better warm).













Then, in goes the Evaporust.





I kept the liquid slightly warm and checked it in about an hour. I used a soft paint brush to wipe the gauge face and see the results. The rust was going away but it needed more time. I see no ill effects of the Evaporust at this point so I dunk the face back in the juice. I let another hour go by ad checked again. At this point I was happy with the results so I pulled the face out and rinsed it off with water. I then blow it off with low pressure compressed air and this is the result. Another hour probably would have removed all the rust staining on the numbers but I didn't want to risk paint flaking off. It should look great now when it is mounted in a cluster and is behind a lens.
















I just thought I would share.


Thanks,

Jason

[marxjunk]

wow..risky..but worth it...

[John Brown]

Impressed. [img]<<GRAEMLIN_URL>>/headbang.gif[/img]

[mssl72]

Not bad at all! I'll have to remember that!