Len, The clutch and diff. do not need to be used together. The clutch is about 4,ooo and the diff and misc parts is around 3,500. This does not include labor. Shad has the diff/ring&pinion at Comptech and I believe it is a direct bolt in for your 6 spd. I have less rwhp than you (433), But I had no problems whatsoever. If you are interested in this part call shad to see if I am correct and I will sell it to you. Thanks, Kip