would anyone happen to know what the average gas mileage is city/highway of a 90 firebird formula 5 speed w/ 305 tpi, not sure what motor it is (l98, lb9???) as well as a 92 rs with 305 lo3, auto? thanks in advance.

 

i get 8mpg in my 84 305 carburated 5speed

 

8 mpg is a little rough there man..... Tune-up time!

The TPI SHOULD probably get better mileage than the LO3 seeing as TBI isnt quite as efficient. I imagine if in proper tune and no SUBSTANTIAL mods such as heads or cam, that you could see 15-18 mpg city. But that's just a guess.

 

I did a 480 mile road trip and got 8.83 mpg with heavy engine mods, time for a tune up /\

 

okay, cuzz i want to get rid of my 92 rs, for my buddies 90 formula, mainly because my mileage is horrible and i was hoping his would be better in the fact that tpis are much more fuel efficient. by the way... my car has 71,000 miles on it, new paint job, 3500 invested, does 6500 sound like a resonable price for it?

 

I don't think you're going to be getting much better gas milage in the Formula than you would in the RS. As long as the cars are both in a good state of tune, one could assume that the cars would obtain similiar gas milage... maybe give or take a few miles per gallon for either one.

I'd say stick with your RS if you've put a good sum of money into it.

 

well my friends put 13000 into his, all reciepts....we put in a new motor 3 years ago, has 40k on it know, we rebuilt the tranny last november, put 4.10s and a posi about 4 months ago, and hes done various other mods,...springs, rebuilt front end, exhaust, ect, and he is getting it painted this weekend. now i know your thinkin..4.10s......horrible gas mileage...but he will get about 200 miles to a full tank, while i only get 160-170 to a full tank and i only have the stock 2.73s. if i do keep mine, im definatly gone have to get some tuning done cuzz im running horribly rich.