[xk49]

I just received my reproduction tach and want to confirm the power for the tach needs to come from a switched source, correct? I'm replacing the clock, so I can't use that as a power source right, because it's always on.

Also, is the rev limit analog markings are set to: Yellow= 4900rpms Red=5000rpms. Is this the right range for the 327? Not even sure if I can move them if they aren't.

 

[alhewitt]

I just received my reproduction tach and want to confirm the power for the tach needs to come from a switched source, correct? I'm replacing the clock, so I can't use that as a power source right, because it's always on.

Also, is the rev limit analog markings are set to: Yellow= 4900rpms Red=5000rpms. Is this the right range for the 327? Not even sure if I can move them if they aren't.

I believe you are correct. On my 65 I sourced the power from the IGN terminal on the fuse block, The ground is straight forward and the tach RPM signal is from the (- negative) terminal on the coil. If it is a factory stock tach with the 90 degree movement they have a red line around 5000 RPM unless it is the L79 tach that have a higher red line.
I switch to a different tach some years ago that has a 270 degree movement. It is a fit-form-function of the original but easier for me to read. Here are a couple of pictures of it... Al

 

[xk49]

I believe you are correct. On my 65 I sourced the power from the IGN terminal on the fuse block, The ground is straight forward and the tach RPM signal is from the (- negative) terminal on the coil. If it is a factory stock tach with the 90 degree movement they have a red line around 5000 RPM unless it is the L79 tach that have a higher red line.
I switch to a different tach some years ago that has a 270 degree movement. It is a fit-form-function of the original but easier for me to read. Here are a couple of pictures of it... Al

I like your larger range for the tach.
Where did you run your tach wire through? Would like to use a preexisting hole, but I don't see any on the fire wall that I can utilize.

 

[Rich-L79]

If the car never had a factory or dealer installed tachometer you have to drill a hole in the firewall for the tach harness.

The standard 283/327 tachs have a redline at about 5200, the L79/L37 use a tach with a 5600 redline. There are a few one-off tachs with slightly different redlines but they are really rare and not really pertinent to everyday factory installed tachs.

 

[alhewitt]

I sourced my tach from a NY company known as Ground-Up or SS396. Here it is albeit in an old catalog. I find it much better than the originals in terms of the display, it is a bolt in with no cutting, internally illuminated with factory lighting. Per Rich's comments you may want to source the factory harness. Tach part number is S-510... Al

 

[Kirk's67SS]

I believe you are correct. On my 65 I sourced the power from the IGN terminal on the fuse block, The ground is straight forward and the tach RPM signal is from the (- negative) terminal on the coil. If it is a factory stock tach with the 90 degree movement they have a red line around 5000 RPM unless it is the L79 tach that have a higher red line.
I switch to a different tach some years ago that has a 270 degree movement. It is a fit-form-function of the original but easier for me to read. Here are a couple of pictures of it... Al View attachment 721809 View attachment 721810

Al may I ask what you have attached to the Top of the Dash in your Car ?
Shift Light ?? and where did you get it ???

 

[alhewitt]

That is the stock clock as found on all 65 and 66 Chevelle's with a factory tach option. Very rare these days and expensive. OPG is making an aftermarket version for under $300... Al

PG is