The tach in my 77 didn't work at all when I purchased the car. I replaced the circuit board and now it works fine up to 3500rpm +/- and then it goes bizerk. M.A.D.'s tech thought I got a bad board so they sent me another which I installed with the same results. Then he said it is probably a resistor in the distributor which is no longer available. Anyone else experienced this and found a solution?

Do you have a tach filter? If not, this link might help: http://my.execpc.com/~rodney1/corvette/

I got mine from the wreckers for $5.Any G.M. will do.

Thanks for your help. My vet suffered an engine/trany transplant by a previous owner and I've been correcting several short cuts they made, one apperantly was not installing the filter. This is my first vette and I had little knowledge about them when I bought it (that's a whole nother story!) I learning!

Would your local parts store have the tach filter complete with connectors for a 1980

Thanks Tom

I ordered the one Rodney Dickman sells for $25. The vet is stored in a trailer for the winter, would love to install the filter to see if solves the problem but it's too tight in there to work and there's too much snow on the ground to get it out and into the garage. Impatiently waiting for Spring!!!