glide vs, 904...bench racing

I run a glide in my 76 Arrow and haven't had any issues in 3 seasons. Yes I do have a spare that came with the car when I acquired it but I haven't had to use it. I change the fluid and filter in the spring, adjust the band according to spec, and chance the fluid again around mid-season. No issues. Car runs 5.70s at 118/119 in the 1/8th and 9-teens and around 146 in the 1/4. As for a side by side comparison of whether the glide is quicker/slower than a 904/727 I can't say. But there has to be a reason for whoever built this car originally decided to go with the glide.