18 spline gear box in a early A body

After grenading third gear in the Liberty prepped 833( because I had the wrong clutch in car). A major decision was made to make the car more bullet proof and I found a great deal on a Jerico DR4 wide gear. Soon after that I found another good deal on the right clutch(Mcleod 10 inch soft loc) that a racer sent back for a rebuild and never reinstalled. When it comes to a clutch, any clutch that hits hard is the wrong clutch and I am not a fan of dual disc clutches( too much mass on input shaft). Any clutch with a lot of static pressure like center force and rag clutches with more than 2600# pressure are going to break parts(a little slip in the clutch is your friend) The clutch that broke my 833 had 2000# static with a sintered iron disc and that hit way to hard. The clutch in the car now is turned up to 1500# on the street(with no slip) and under 900# at the strip. My 66 Dart has gone from a high 10.9, 11.0 car to 1.49 60ft 10.709 at 126 with just clutch adjustments and car is run through a full exhaust and street trim, just take clutch pressure out an bolt on the 9" by 26" slicks and gets over 13 mile to the gallon on pump 93 with the 4.10 gears.