gauge cluster change

[r15racer]

Do I have to change the complete under dash and under hood wire harnes to go from a cluster with warning lights to a cluster with gauges in my 87 silverado? it does have a/c

[Captkaos]

What year is the cluster coming from?  The 87 has EFI and you need the speedo if the donor doesn't match.  Out side of that, you need to verify the pins on the cluster work with what you have and you may have to repin some of them.  And you will need to change the senders in the motor for the gauges.

[r15racer]

The cluster is from an 86 and Im taking the EFI off and putting a 355 in it

[Captkaos]

Should be identical.  Just verify the wiring from what I posted in the tech pages.