Which part to buy?
 

My car is a 91 LX 5.0 convertible with stock 2.73 gears and an AOD with a TransPak. My engine is nearly bone stock and is only driven on the street. For more torque on a college-student budget, should I be in the market for a torque converter or a set of 3.73s? If anyone answers torque converter, what the hell does it actually do? Thanks much for any help!

If your going to make one mod on your car go with the gears - most everyone goes with either 3.73's or 4.10's for the AOD cars. You won't beleive the difference in your car after dumping your 2.73's

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1965 K code coupe - numbers matching - restoration ongoing. 1987 LX notch, stock heads and intake, 3.55's and typical bolt on's 13.89@100.25

I would agree. You will feel the most increase with the gears, and then when you eventually do get a new converter, it will be even more apparent. A torque converter works like the clutch on a manual tranny, it allows the power to be disconnected so that the tranny can shift, it also builds up the pressure that the entire slushbox runs on. Think of two fans facing each other, if you turn one on, the other will spin b/c of the air going by it. Thats like the torque converter, except it's filled with fluid for better transfer. It allows for much faster shifts, but you loose power by the nature of using a fluid to transfer that power. The loss of a manual driveline (correct me please) is something like 16-18% or something, and a stock auto 22%. With a torque converter that stalls (it stalls when everything is spinning at the same speed, no slippage) closer to the engine's peak power, you can lower that loss closer to a manual. Check out this article, it explains it well: http://www.fordmuscle.com/archives/2...er/index.shtml