Can I come under 13,5 ??

My car is right now on a 3,55 gears change( I do it myself) Bought it used...wanted 3,73 or 4,10 but 3,55 must bo ok?!. H-pipes and Mac 1 5/8 is comming to(used). And a hurst shifter! from the middle of next week I have a new garage...looking for some weight to throw away from my stang. The battery to the trunk also! What more did I need?????????

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-87 GT, K&N, 5-speed, Walker exhaust, no air silencer. timing
75000miles. This vinter 3,55 and mac 15/8 and H-pipes
14,61 and 95,59mph