From what I understand about these transmissions is that the c4 is stronger and lighter but you lose your overdrive, so your rpm's will be higher. The c4 is a good transmission but if you want to stay with a good aod lentech makes one rated to 600 hp for $1995.00. If you don't have that much money get the c4.
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James Cox
nochevy@hotmail.com
1991 Mustang LX
Best 1/8 time on motor 7.686 @90.20mph