‘64 K20 factory tach
 

Have a ‘64 K20 with a factory tach. Don’t know what engine was original. Has a 454 with hei ignition now. Tach needle moves but only goes from 0 to about 1500 rpm. What should I be checking ?

Re: ‘64 K20 factory tach
 

You need to pull the gauge cluster and remove the tach to see if it is for a 6 cylinder or an eight. They are different tachs and cannot be interchanged.

There should be a sticker on the back that will tell you.

Pictures would help...

Re: ‘64 K20 factory tach
 

I will have to take some pics. And sounds like pull the cluster. Could maybe do some research on my vin and see what engine it came with also I guess

Re: ‘64 K20 factory tach
 

The VIN will not tell you what engine the truck came with from the factory. Also, most gauge clusters with factory tachs came in the medium duty trucks. So your gauge cluster may not be original to your truck. And an original tach will not work with a HEI.

Re: ‘64 K20 factory tach
 

So it really doesn’t matter what tach I have then if an original won’t work with hei

Re: ‘64 K20 factory tach
 

I have a '65 V8 tach that does the same thing. It's very stable, smooth, and accurate- I checked it against a Sun tach/dwell meter. Only problem is it won't go higher than 1500 rpm. Not sure if someone repairs these or they are just not worth the cost/effort. Should I just buy a new repro?

Re: ‘64 K20 factory tach
 

Call RedlineG.com
He should be able to help.

Re: ‘64 K20 factory tach
 

if you decide to change up to a new one, check out my tach install thread

http://67-72chevytrucks.com/vboard/s...d.php?t=499570