Do our original stlye tachs work with HEI?
Will they read/be accurate just by hooking into the 'tach' port on the dizzy cap?
Will they read/be accurate just by hooking into the 'tach' port on the dizzy cap?
CK5
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Old Tach-New Ignition Question
- Thread starter vtblazer
- Start date
I think you need one of these....
Almost positive I found that in a thread on the 67-72 Board.
Almost positive I found that in a thread on the 67-72 Board.
Should be the same. Years ago i've had vehicles with points dizzy's and swapped in an HEI and did nothing more but hook to tach lead and works perfect.
Works fine on my pickup as well. The stock tach didn't have any issues with the HEI or the MSD that was added later.
Weird.....I had a factory tach that was WAAAAY off with a later model ignition / dizzy.
I wish I had a link to the original thread, it talked quite a bit about the hows and whys of retrofitting new electronics to the old tach.
SEARCH, I guess....
I wish I had a link to the original thread, it talked quite a bit about the hows and whys of retrofitting new electronics to the old tach.
SEARCH, I guess....
WORKS! 
The cable coming from the tach had two wires taped together, one brown, to the coil and the other pink, for power I guess.
Cause when I hooked up just the brown, nothing but when I powered up the pink, up it went.
Seems fairly close to reading correct.
Don't need perfect, just wanted it to work.
Thanks for the input doooods!
The cable coming from the tach had two wires taped together, one brown, to the coil and the other pink, for power I guess.
Cause when I hooked up just the brown, nothing but when I powered up the pink, up it went.
Seems fairly close to reading correct.
Don't need perfect, just wanted it to work.
Thanks for the input doooods!
bp71k5
3/4 ton status
Ah, does this mean I can get the old style tach and have it work with my HEI? I also thought you needed an adaptor like Greg mentioned.
Greg,remember Steve Chin,he's the one who cam up with the difference in the wavelengths between the points and a HEI signal.
One is a Sine wave.And one is the square one.
I'll see if I can find the post
One is a Sine wave.And one is the square one.
I'll see if I can find the post
I dont have an adapter and mine works beautifully with HEI!
Looks like the tach is messing up your fuel gauge though.....
nope, the sender was focked up when that pic was taken.Looks like the tach is messing up your fuel gauge though.....
