I'd tell your friend to go w/ the pulleys, gears (3.73 for manual and 4.10 for auto) and a K&N filter - the stock box is basically a "cold air induction kit". As long as he's got a kicka$$ stall converter his auto will be plenty fine. The auto would be better too if he plans on bracket racing it.
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'90 5.0 LX - heads, intake, cam, fuel delivery, gears, full exhaust, pulleys, ignition, drag springs, front brake upgrade, a/c delete, K&N cone filter charger, Corbeau racing seats
1/4 mile: 12.29 @115
60': 1.78
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