I wanted to put a 160 thermostat in a 94 z is there anything i should do before or after doing this.

 

Protect your opti from spashes before you take it out, get the correct long thermostat and check for air/bleed the system when you are done.

My personal way of changing the thermostat is to start with the system completely cold. I don't bother to drain any coolant. I pack absorbent rags or towels all around the thermostat housing. I remove the housing and let the rags catch the small amount of coolant that escapes. Replace the thermostat and close the housing. Put the elbow and whatever else was removed back on. Estimate the amount of coolant lost and add anti-freeze of the same amount into the remote reservoir. Very little air, if any, seems to get into the system this way and I usually don't have to worry about it. Any small amount of air will purge itself after several themocycles. Keep an eye on the temp gauge as you drive it the next few times to be sure things are ok.

 

Like Shoebox said! protect the opti by stuffing rags under the thermostat.

Also be very sure you buy an LT1 SPECIFIC thermostat. If you go to the parts store and they say it will be $2.50, it is obviously the wrong thermostat.

 

Will this effect my computer in any way

 

Only that it will sense a generally lower operating temp. There is nothing you have to do with or to the computer.

 

will this give me much in the way of horsepower gains

 

I would not count on much or any just by the thermostat alone (especially in winter). The real reason behind the lower temp thermostat is so you can make use of more aggressive timing without pre-ignition. So for real horsepower gains, programming would go hand in hand.

 

Not unless you change the temp at which the fans come on, or get a manual fan switch

Even then I'd say nothing you'll feel on the butt dyno

 

Thanks for the info guys.
Long live the f-bod