Sky, Killercanary was right about m&ff getting 10hp from removing 1 quart, but what he forgot to mention was that the car had too much oil.
Just for fun, If I were you, i would run it with open headers, I would Think About 10hp gain
later...
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1988 Mustang GT, T-5
No Smog Pump (Shorty Belt), Dumps At The End Of Stock H-Pipe (Sounds Mean), K&N Air Filter (Stock Air Box, Removed air silendcer), 198.9 rwhp @4200 (235 Motor!!), 285 lbs-ft @2900 (336 Motor!!!).
My Stang This Is What Dynomax Ultra-Flo's Do