[98SteedaGT]

This is from Steeda's website FAQ section for instaling Pulleys

-----On automatic transmission cars, the engine must be held from turning by holding the torque converter. The torque converter can be accessed by removing a plug towards the front-drivers side of the transmission. (Consult a service manual for more information). Hold the torque converter from turning with a 14mm wrench.----

I believe on a manual you should be able to brace the wheels from turning and put the car in a high gear like 4 or 5 and that should keep enough back pressure on the flywheel to not allow the crank to turn... I don't deal with manuals much, so, if it doesn't work or breaks something, don't get mad at me...