I recently did a Th350 and 3,200 stall converter swap in my firebird, and now my car revs up a lot quicker, and I have this problem......as soon as I floor it, the tach starts to bounce all over the place. Whats the deal?? Its the factory in dash tach hooked up to an MSD 6A box. any ideas?? i need to fix this, I'm running the car the 19th on nitrous and a tach would be a nice thing to have.

 

First, make sure your tach filter has been removed. If it still acts erratic, you'll have to purchase a tach adapter from MSD. There are two available, #8910 and #8920, depending upon your application. I needed the #8920 to make my factory tach work in my car with a 6AL box and their billet distributor. Before I installed the tach adapter, anything above 6,000 rpm, my tach would go to zero.