Because I don't know of any other side hung rear fuel bowl with an accelerator pump. If that was available I could have pieced one together myself. Probably not for the price of this one though.
I’ve been through two of them. You need to verify the tune up. I have had them on the phone several times. If I have to use email to talk to anyone like that I won’t do business with them.
Their stuff is very very nice and the price is right. The problem is getting them. So far since the Covid, they haven’t been getting orders filled.