hey all , i just bought one of those bosh tachometers that looks like the old super sun tach ,i hooked it up and its reading low on rpm, i rev it up to were its around 2000 grand and its only showing 1000 rpm, does anyone know if i need a filter for it , im running the old gm hei thanks for the help
tach reading low rpm
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What do you have for a distributor. My Oer reproduction tach worked like crap with my Pertronix ll until I had Redline changed the guts. Stock factory worked but looked like hell. Actually Jegs put it on their dime. That's what I call excellent support
hi bill im running an old stock hei dist i took my car off the track and put it back on the street , when i was racing it i had my monster tach running through the msd box and it was fine
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All HEI cars until the early 80's ran filters. The tachs before HEI ran off the resistor wire voltage so GM equipped them with filters for signal and protection for the older tach that were still in use. David Ray can speak better on that if he pipes in. Rick and I had issues with our tachs. He with his old Sun tach and I had an issue with my OER repro rollers tach after we went to Pertronix. OER only guarantee their tachs on points unless it was used for HEI. Rick bought a new version of a Sun look a like to fix his issue with the old SUN and I had the guts changed by Redline Gauges to a new and very accurate tachometer but kept the factory roller stock look. I tried a factory HEI tachometer filter, caps and resistors on my car but it didn't work. Some tachs just don't work with some dizzy's if they were just not built to run on them.
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