C4 identification and build questions

Hey, I have found a C4 that I am looking to buy, but I am worried that it is not the Hardend shaft 26 spline. I have counted the splines, it is a 26. But how can I tell if it is hardend or not. It came out of a early 70's 3/4 Ton Van with a 302. I got the casting number from the guy who has it in his garage, I believe it reads
C8ZP-7(0 or D)0Q7-A

I would really appricate your help, I am planning on rebuilding it and putting it behind my 351C Twin Turbo. Can a C4 be built to hold 650-700 HP, and what type of parts am I going to need, this will be my first tranny rebuild, but I will have a spotter who has built plenty tranies before.

Or Would you Guys recommend going with a C6? It is going in a 3200 lb car, with 3.50 read end

Thanks

Test the shaft by trying to scratch it, if you cant...its hardened. I think only 4x4 trans with a bolted on tail shaft used them from the factroy????? For it to handle that kind of hp, it will need some mods. There is some great info on here on to convert it to a full roller trans, welding up the front drum, clutch pacs, valve body's, servos...etc. try a search for "roller c4" or something, and dont forget to read the monster c4 post[img]/phpBB/images/smiles/icon_tup.gif[/img]

http://www.fordmuscle.com/phpBB/view...orum=13&26

<font size=-1>[ This Message was edited by: fogged408w on 6/3/04 1:53pm ]</font>