autometer tach and dash tach,which one is right?

[Rynb15]

I installed a autometer tach the other day. Well yesterday i finally got out to play with the 5.0. I noticed when i get in to the higher rpms, above 5k they are diff. The autometer guage keeps pulling at the same speed and when i hit 5800 on it, the dash tach reads 6300 but when i watch the dash tach it goes from 5300ish rpms to 6k almost intantly. I would imagine the auto meter guage is right. I hooked it up right to the coil. Just needing some feedback

 

[87'GTstang]

The stock tach can be off by as much as 10%, trust the autometer one. A quick "jump" in rpms isn't a characteristic of the stock tach however.

 

[Rynb15]

thats what i was thinking. Thanks

 

[1SLO306]

yup trust the autometer tach.

plus the rev limiter is 6250

 

[kreacher5.0]

Ive had the same problem. Mine is off about 200rpm at ideal then when it gets on up to about 6000 its way off the stock tach is about 7000

 

[01silverbullit]

When my autometer says 5800 my stock tach says 6100 so im sure the autometer is right

 

[kr8zstang]

My tachs read the same till about 3k, then the stock tach climbs much faster than the autometer. When i hit 5k on the autometer, my stock reads over 7k!!
I'm sure the autometer is more accurate or i would have replaced about 12 engines by now!

 

[Rynb15]

ok, i feel much better now. Im going to the track tomorrow and dont want to blow anything up

 

[Strype]

My stock tack is off 200-300 rpm at idle...

 

[88_GT_5_oh]

i mounted my tach to block my stock one cause i don't even care what its at lol.... i looked one time and i think at 3000 rpm on my sunpro tach the stock one is like 3300 rpm

 

[1SLO306]

my stock tach says i idle at 1500 and when my autometer tach is at 2500 the stocker is at 4500