We make & sell a thin, heat-treated 1" wrench specifically for this application. Less expensive than anyone else's, too.
$22.00 + $3.00 shipping. Got tired of trying to wrangle a wrench between my Holley & the firewall on my racecar and garfing up the fittings, bowls & firewall.
You can PM me here, or email me directly at topside340@yahoo.com, or look me up on ebay as seller name "topside340", if you want one.