How do I wire up.1970 chevelle SS with factory tach

which or what emblem theirs a few //// or ask a dealer /body shop/ catalogs such as opgi --rps ---summit--brothers -- yearone --etc

would try and bring the temp down by lower degree thermostat hi-volume water pump bigger radiator maybe even double check timing sounds like you might be boiling fuel and hydro locking it

You must remove the starter and oil filter. Then do one side at a time remove mtr. mount bolt and jack up eng. and bring header up from the bottom.

The original tachometer was powered from the negative side of the coil.
I don't know how many wires you have to work with, but the one that powers the tach should go to the pigtail wire on the harness for the coil - dist cap.

Hello
Due to the age of the car we do not have diagrams available for free on the Internet. Below you will find a source for the original factory repair manual which would have all the information in it. Here is the link to the manual.
http://www.faxonautoliterature.com/1970-Chevy-Car-Repair-Shop-Manual-Chevelle-El-Camino-Monte-Carlo-Nova-Caprice-Impala-Corvette-P10695.aspx

2009 CHEVROLET SILVERADO C1500 4DR TRUCK WITH 4.3L ENGINE AND STANDARD AUDIO SYSTEM

Remote Start
WIRE COLOR POLARITY LOCATION
Battery RED/WHITE (+) IGNITION SWITCH HARNESS
LOW CURRENT, FOR HIGH CURRENT USE RED/BLACK AT VEHICLE FUSE BOX
Ignition 1 PINK (+) IGNITION SWITCH HARNESS
Accessory 1 BROWN (+) IGNITION SWITCH HARNESS
MAY BE YELLOW ON SOME MODELS
Accessory 2 PINK/BLACK (+) IGNTION SWITCH HARNESS
FOR REMOTE START INTEGRATION
Starter 1 YELLOW/BLACK (+) AT MODULE UNDER HOOD BEHIND DRIVER HEADLIGHT
NOT FOR REMOTE START, FOR REMOTE START INFORMATION
Starter 2 PINK/BLACK (+) IGNITION SWITCH HARNESS
FOR REMOTE START INTEGRATION
Anti-Theft Type GM PASSKEY III® ANTI-THEFT SYSTEM
Anti-Theft Descript THE KEY SENDS AN RF SIGNAL TO THE BCM MODULE THROUGH AN ANTENNA LOCATED AROUND THE IGNITION CYLINDER
Key Sense PINK (+) IGNITION SWITCH HARNESS
Tachometer WHITE (-) AT IGNITION COIL
Speed Sense YELLOW/BLACK (AC) AT ECM MODULE UNDER HOOD ON DRIVER FENDER
BLACK PLUG PIN #57
Parking Lights LIGHT BLUE (-) AT VEHICLE LIGHT SWITCH
Brake Lights LIGHT BLUE/WHITE (+) AT SWITCH ABOVE BRAKE PEDAL
IGNITION MUST BE ON FOR THIS WIRE TO TEST
Reverse Lights DARK BLUE (+) AT BCM MODULE UNDER DRIVER DASH
Horn TAN (-) IN HARNESS AT STEERING COLUMN
ALSO AT BCM MODULE UNDER DRIVER DASH
Modules
WIRE LOCATION
Please select another category
Doorlocks/Windows
WIRE COLOR POLARITY LOCATION
Power Unlock WHITE (-) AT BCM MODULE UNDER DRIVERS SIDE OF DASH
THIS WIRE UNLOCKS THE REAR DOORS ONLY, WILL REQUIRE A 5-WIRE SET-UP IN EACH FRONT DOOR TO INTEGRATE OR A SERIAL DATA MODULE FROM AN ALARM MANUFACTURER
PowerLock LIGHT BLUE (+) AT BCM MODULE UNDER DRIVERS SIDE OF DASH
THIS WIRE LOCKS THE REAR DOORS ONLY, WILL REQUIRE A 5-WIRE SET-UP IN EACH FRONT DOOR TO INTEGRATE OR A SERIAL DATA MODULE FROM AN ALARM MANUFACTURER

i would use a DLPK module

DLPK (2009 Chevrolet Silverado)
W2W
CC-Heated Seats Activation
DL-Arm Factory Security
DL-Disarm Factory Security
DL-Door Lock Control
DL-Door Unlock
DL-Driver Priority Unlock
PK-Immobilizer Bypass-Data No Key Req'd
RS-RAP Shut Down (Remote ACC Power)
RS-Tach / RPM Output
SS-Entry Monitoring ALL Door Pins
SS-Entry Monitoring Driver Door Pin
SS-Entry Monitoring Front Door Pins
SS-Entry Monitoring Hood Pin
D2D
CC-Heated Seats
DL-Arm Factory Security
DL-Disarm Factory Security
DL-Door Lock Control
DL-Door Unlock
DL-Driver Priority Unlock
PK-Immobilizer Bypass-Data No Key Req'd
RS-RAP Shut Down (Remote ACC Power)
RS-Tach / RPM Output
SS-Entry Monitoring ALL Door Pins
SS-Entry Monitoring Driver Door Pin
SS-Entry Monitoring Front Door Pins
SS-Entry Monitoring Hood Pin


Hope helps.

there should be a ground wire going from battery neg. terminal to the body not just the engine check to see if wire there and just broke or bad connection

Check power to the instrument cluster, do you have power to the gages?