I had a 305 TBI in my 89 firebird. Its good on gas but it poured smoke out which that was after 100,000 miles which 305 are very good for that because of the rings and seals. I found out that a rebuilt 350 was cheaper then rebuilding my 305. So if your looking for good gas milage then the 305 is good on that but my 305 never had the power, I mean it would go when needed but its nothing like a 350. Hope that helps you in some way.