How much power can a stock 8" rear take?
and how much power can a C4 handle?

 

Dunno bout a C4, but I heard someone say an 8" will take 500rwhp. But I have no idea whether it's true or not. A lot of it will depend on how it's used. Launching on slicks with a transbrake or clutch dumps and it won't last as long as street tires with light launches. It'll also depend on the axles you use.

 

Depends on a few things. But, 400-450hp can flow through an 8" without too much trouble, as long as it's isn't beat on (hard shifts from drag racing, for example), or coming from a big-inch engine. The C4 would depend completely on the build. Stock isn't much more than 300hp, but they can be built to handle a lot more.

 

Something to think about. Ford used the 8" for up to 220 hp. Anything more than that (K-code {271hp}and big blocks) got the 9". Ford had to be more concerned about reliability than a single modifier person, but.... it's something to think about.

 

I know some drag racers prefer the c4 over the c6 because it has less power loss through the tranny due to being smaller and lighter. I can only assume they found a way to plant some pretty good power through them.

 

you can build the c4 to prlly handle about 4-500. rearend, i would go with a 9in anything over 300 just to be safe. and i assume its not your weekend cruiser if your building past 300hp

 

The C4 has been built up and can handle upwards of 900hp. It can be done. Look at Performance Automatic.

 

Here is one that will do up to 1000 HP.
http://www.dynamicracingtrans.com/fordtranny.htm

I have also seen DIY rebuild kits to 800 HP.

 

my 400-425 hp 302 chewed up and spit out my worn stock C4 (blew the planetaries out and the clutches were shot). but HD clutches/steels/bands, HD servo, and a good shift kit they will handle oodles of power. stepping into a better planetary and hardened input shaft ups the power handling even better

 

If you wanna rebuild it yourself, here is a good article.
http://www.mustangmonthly.com/projec...ssion_buildup/

And a video you can buy.
http://smartflix.com/store/video/373...ssion-64-to-69