Question about an aftermarket exhaust

Does anyone know if exhausts from either an XJ650 Maxim or an XJ750 Seca will fit on a 1982 XJ750 Maxim. The exhaust on my project one is rotting out, mufflers aren't salvageable at all and I had to cut what was left off, now I need to decide if it's worth trying to fix what's left or replace it but I absolutely want to keep the 4-2 exhaust. All the ones I am finding (such as this: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/151224525419) say either 650 Maxim or 750 Seca. So my question is, what's the difference since it appears as though the engine is basically the same between them? I am more than okay with just fabricating hangers and mounting brackets but I'm not looking to butcher an entire system if it won't fit at all.

 

the exhaust headers (front pipes) are the same for the maxim and seca 750. but not the same as a 650.
the rest of an after market system will fit up it will be needing hangers made to suit where you mount mufflers

 

Awesome, thank you very much!