Not sure if anyone local sells the old Supra 280 pump which would be exact?

That pump just looks like it relies on the compression fitting and pushlock rigidity over a short length to mostly retain it. The rubber cushioning between the hanger and the pump, plus the stock boot wedged in, must do the rest to stop it rattling around.

For the Walbros here, turned a thin plastic ring to centre the pump and hose-clamped that to the hanger to retain it - and avoid any possibility of distorting the body.

The SS hardware kit is a bit red hot I must say, ha! You'd probably buy 10 inspection cover kits for under $10 at a fastener shop.