Beefing Up 904

Math is hard for some people; but geometry is impossible. If you take the time to measure a 904 and a 727 clutch disc do the math, subtract the difference, You'll find that the 904 plate is a little over HALF the friction area of a 727; exactly only 5/8 the area. A six plate direct clutch 904 is 75 square inches of friction material. A six plate 727 is at 118 square inches. A four plate 727 is 79 square inches; a little bit more than a six plate 904. To get to six plates in a 904 it requires a lock up trans as a foundation for parts. And then you need a dummy lockup converter..more expense. A lot of trouble to get to a point that is still weaker than a stock 727. And for what? 1/8 of a second in a quarter mile? The friction material in a 904 has an outer radius that is smaller than the inner radius of a 727. You can easily drop a 904 plate right thru a 727 plate. Consider the difference in the leverage a 727 plate has since the radius is a lot larger. There's more to strength than square inches; it depends on how close to center those inches are. Based on square inches plus leverage, a 727 plate is over twice as strong as a 904 plate.