C4 tips for durability

[stangman92gt]

We are building up a C4 (157T) for my friend's 86 Coupe with the equivalent of a GT40 crate engine. The car is a weekend driver with about 50/50 highway/track time. More engine modifications are in the car's future. Right now it runs high 13'[email protected] mph through the "freebie" C6.

What would like to know is what kind of modifications are needed or recommended to make the C4 a reliable transmission at the 300-400hp level?

For reference the C4 is a 1967 originally behind a 289 in a Mercury Cougar.

Thanks very much....

 

[mustangdave]

Some things to consider are a "C" servo, shift kit, and better clutches.

 

[mustangdave]

Check this page a little ways down and you will see some of the available upgrades such as low drag planetary sets w/needle bearings,etc...
http://www.tciauto.com/ford/ford_c4_c6.htm

 

[351LX]

Here is a link to some interesting reading http://www.carbdford.com/viewtopic.php?t=5731