What is your gas mileage like after your change? Also add what tranny your have as well as rearend gear. I want to know what I would lose.

 

If I keep it around 65mph on the highway and don't get on it..about 25mpg. I have a 6m.

 

You left some info out.

 

On the highway your gas milage wont change. In normal "having fun" city driving I'd expect it'd go down a fair bit...maybe 20% is a good guess.

 

My gas mileage went to the crapper after my H/C. If I don't get on it, I get slightly less gas mileage than before ~280 per tank rather than ~300+ on the highway. If I am getting on it though (driving how I normaly do) I get only 180 per tank, rather than the 220+.

ARE Stg II H/C. T56, 3.42

 

300 if your easy on it with a vig 3600
150-200 if you drive like you mean it... and with 400rwhp how can you not?

 

Man, that just makes me want to buy me a turbo and bolt it on. I can go 425 on a long distance highway on about 14.5 gallons. At least with the turbo my gas mileage on long trip won't suffer.

 

M6, 4.56 gears and 24 mpg at 75 to 80 mph with the rpms at 2400. <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />