Tachometer crazy?

[swilk]

I just recently got my DA running smooth as can be. It has great power and drives great. I even fixed my hunting idle and high idle today! However, when I'm driving it, or in neutral, if i give it a good punch, my RPM's dodge all over the place, and I can't tell what my RPM's really are. it goes NUTS! I can tell my engine seems to be running right, very rarely does the tach going crazy actually seem like the engine is too, but is there a common cause for this?

 

[TheSkygun]

What has been done to the car and has the gauge cluster been messed with at all?

 

[swilk]

I had to pull the cluster to put a new MPH cable for the tranny. Mine was whining real bad. But I didn't touch the RPM's. It's an engine swap from a 93 LS but the same engine. I bought a dizzy from a friend, it works fine but doesn't bolt down really. I had to use a big washer to hold it in place at the correct timing. Possible that's causing my spaz's?

 

[da9 b20 beast]

why doesnt your dizzy bolt down correctly?

 

[keblung]

i have the same issue with my 92 ls also.i havent done anything to it though.its still completely stock