i have a 1985 iroc z just put new 350 have a issue when i step on the brake the dash lites up this is probley do to a short but any good place to start would be a big help thanks:)

What do you mean by "dash lites up". If it is the Brake Light Failure indicator, I would suspect the Line Pressure Sensor has tripped because you have low pressure somewhere. If all your Lights tend to get Brighter I would suspect that you have a Bad or NO Ground on the Brake Light circuit.

all the lites in th gage cluster oil, speed, tac, temp, also left blinker also center consol ashtray lights my blinkers still work

blinkers work all the way around and they flash at the same speed on both sides?

yes

climb under and look for loose grounds on the back of the dash gauge cluster.

If you suspect a ground problem, use a Digital Volt Meter (DVM) to measure the voltage drop between your various grounds and the negative battery connection. You'll want to do this with the circuits loaded in various ways (lights on, brake depressed, etc.). In all cases you should very small voltage readings (< 0.05 volts or so). If you see higher readings you've found a bad ground. You'll probably need to extend your meter leads some way. I have about a 10' piece of wire with allegator clips on it that I use. I've also used jumper cables or an extension cord.