Barry... Barry .. Barry...RollRoll
Why would you think that a 400A seat would fit a 750..??
Because they both have torque converters and automatics..??? lolol..

As I remember from Princes abortion..
I believe the 400As didn't have a hinged seat.. they slipped on with brackets at the rear..
(maybe not.. it's been awhile.. but I think so..)

Thats not saying that.. with some sheet metal screws and some muffler brackets... .. you couldn't make it fit though...

Build it the way you want it ..... then learn how to ride it like you own it..
www.lowridersbysummers.com