Thanks Dan, I was curious why my 6400 didn't have a 9 1/2" and if maybe the 7" had the same bolt pattern as the 9 1/2 and someone swapped the smaller one into it. I'll just see how it works I guess and if it seems too weak I'll think about trying a 9 1/2. The nice thing about these is the ease of installation. It's all back together except for the control valve diaphragm. The kit I got had a different one entirely so I sent a picture of it to the store and they said the 347550 came in two types and they had the right diaphragm and could ship it out right away. So just waiting for that now.

Still wondering if I should take apart what is underneath of that control valve diaphragm or call it good. I did take apart all the stuff below that pressure cylinder and replace those parts. Thanks for the help and I'll let you know if I need any more help

1949 Chevy 6400 two ton, 2 speed rear end, 235 engine, 13 foot hydraulic dump bed.