I am swapping from a 89 TBI to a 90-92 TPI. What is the hose off the front of the manifold for? (Next to the coolant temp sensor)

Heater or something?

 

Yes. It runs to the throttle body, which runs to the heater control valve, which branches off to the heater core and the oil cooler(?) or back to radiator if there is no oil cooler. A common mod is to bypass the throttle body coolant supply, feeding it straight to the heater control valve.

 

I dont have all that other crap, so I will just do that then.

Thanks.

 

Or you could just eliminate your heater entirely. I did and I have not missed it yet, 2 years... Like it gets cold here anyway!!!