What factory tach will hook up without mods for my 74 620

[chavezYchavez]

Guys,

finding a factory tach for the little 620 is killing me and like looking for a needle in haystack. My truck has the L16 engine used from 1972-1974 in it so what years interchange for the factory tach without mods? Also what is the correct Part# for the tach?

CYC

[ggzilla]

Any 620 tach will fit. You can use a 1200 tach if you modify the wiring, but they are even more rare.

[datzenmike]

Guys,

finding a factory tach for the little 620 is killing me and like looking for a needle in haystack. My truck has the L16 engine used from 1972-1974 in it so what years interchange for the factory tach without mods? Also what is the correct Part# for the tach?

CYC

 

The tach wasn't an option until '76 so it will only fit the '76 and later trucks without mods. It will fit the earlier truck dash by removing the delete cover but there won't be any wiring in place to make it work or connect to the dash lights. After '76 the plug is tapped up behind the instruments and is in place if a tach is added.

 

24840 B6400 is a factory tach 'kit' for pre '67 trucks and is over $200

24855 B8000 is the factory tach for '76 and up trucks with wiring already installed. Also over $200.

 

1 is ground.

2 is power (ignition switched)

3 is power from dash lights

4 & 5 is wired in series between the coil - and distributor

 

 

This is likely the factory 'kit' for pre '76 trucks as it does not have the 6 wire plug on it.

 

 

 

This is likely the factory tach and clock with the 6 wire plugs on them:

 

[chavezYchavez]

The tach wasn't an option until '76 so it will only fit the '76 and later trucks without mods. It will fit the earlier truck dash by removing the delete cover but there won't be any wiring in place to make it work or connect to the dash lights. After '76 the plug is tapped up behind the instruments and is in place if a tach is added.

 

24840 B6400 is a factory tach 'kit' for pre '67 trucks and is over $200

24855 B8000 is the factory tach for '76 and up trucks with wiring already installed. Also over $200.

 

1 is ground.

2 is power (ignition switched)

3 is power from dash lights

4 & 5 is wired in series between the coil - and distributor

 

 

This is likely the factory 'kit' for pre '76 trucks as it does not have the 6 wire plug on it.

 

 

 

This is likely the factory tach and clock with the 6 wire plugs on them:

 

 

 

Thant is great I sure appreciate it that enlightens me more now.

CYC

[mr68gts]

Your correct, the one with the mini harness is the factory installed tach for a 76. (I'm looking at the one out of my unmolested 76 right now! and my uncle bought the truck from the dealership my father worked at back then!)The one with the individual wires is an add on for a truck not set up with the later harness to accept it. BTW, I believe the tach is the same, the only difference is the method of hook up although I cannot confirm at this time.

Paul

 

The tach wasn't an option until '76 so it will only fit the '76 and later trucks without mods. It will fit the earlier truck dash by removing the delete cover but there won't be any wiring in place to make it work or connect to the dash lights. After '76 the plug is tapped up behind the instruments and is in place if a tach is added.

 

24840 B6400 is a factory tach 'kit' for pre '67 trucks and is over $200

24855 B8000 is the factory tach for '76 and up trucks with wiring already installed. Also over $200.

 

1 is ground.

2 is power (ignition switched)

3 is power from dash lights

4 & 5 is wired in series between the coil - and distributor

 

 

This is likely the factory 'kit' for pre '76 trucks as it does not have the 6 wire plug on it.

 

 

 

This is likely the factory tach and clock with the 6 wire plugs on them:

 

[ggzilla]

That is a Datsun 1200 tachometer, it has the induction loop wiring (4&5), which matches the 1200 dash wiring harness.

[JDM510]

like i said i have the 1200 tach with 620 lens in perfect working and restored shape for 90 shipped let me know if any one needs it!!!!

 

 

 

[chavezYchavez]

like i said i have the 1200 tach with 620 lens in perfect working and restored shape for 90 shipped let me know if any one needs it!!!!

 

 

 

 

 

Sent you a PM replying I want the tach provided you have the wiring to go with it for my 620 truck.

thanks CYC

[ggzilla]

Do you have the wiring for that tach? It has two lights, but also the induction loop.

[JDM510]

yes i have the bulbs and i but when i got the tach it had no induction wire... plus isnt it just a regular peace of wire????

 

but yeah you will have to wire this up your self and your 620 posibly will not have the mentioned wire harness taped with the blue tape to the factory harness....

 

so that means you will have to climb under the dash with a test light and find witch wires do what (lights, 12 key on pwr,) find a ground source.. and i may be forgeting someting???

 

 

i had this tach hooked up and it worked perfect in my 620 with a l16 just like you have.. just i got another tach i mounted in their i like better..

 

 

soo yeah i guess i can put the lights in and run the induction wire for the buyer befor i ship it . i also think i still have the flat lens for the 1200 if someone needs this for their 1200

[chavezYchavez]

Rcved the tach better that advertized thanks.

 

Question now is the induction wire 4&5 how exactly do they hook up? I know it says coil and distributor but which one goes where?

cyc

[ggzilla]

For the tach with induction loop, it goes to ONE place, you wire the coil positive wire through it.

 

[chavezYchavez]

For the tach with induction loop, it goes to ONE place, you wire the coil positive wire through it.

 

 

 

Thanks alot for posting it helps allot now if it ever warms up around here will install that tach

CYC

[chavezYchavez]

delete