My buddy at work has a 91 rs tbi 305/5 speed that he wants to sell me for $600. It has been setting for 3 years. It smoked before he parked it so i'm planning on doing a "stock" rebuild on it (as long as the cylinder walls can be honed) and retaining all the tbi stuff. Is there gaskets and stuff in the tbi unit that dry out like a carb? Also, will bolts on like full exhaust, k&n open element make the mpgs go down? I know a tbi 305 is a dog but I really want the car for mpgs as my lifted 04 f150 5.4 gets about 10 mpg.

Thanks for any info.

Exhaust and open element should get you a little bit better gas mileage, make sure the u2 sensor is good and all the plugs and wires if you want good mpg

With the rebuild, Plugs, plug wires, new air filter, change the oil after the first 500 miles, then again at 1000, then on the normal 3000-5000 mile schedule depending on if you use full synthetic motor oil or not. Make sure you completely purge the fuel tank and lines before trying to start it. Bad gas will cause all kinds of problems. 3" exhaust and headers will free up around 10-20hp on the motor and should help get a bit better fuel mileage as well. If nothing else, the car will breath better and run better overall. Also, since the heads are coming off, look at putting 1.94 valves in them, it'll help breath better. Super Chevy did this when they built their 300hp 305 motor.