Yep. Disconnect that and aim the spout into a bottle or a small container and get someone else to roll the engine over. If there isn't much gas or none at all, change the fuel pump. If there's gas, check the filter in the little section where you removed the fitting.
And, I know it sounds dumb, but make sure there's actually fuel in the tank. Fuel gauges/senders fail. When mine did it showed more fuel than was in the tank.
What fuel pump are you using? Wouldn't a stock 87 would have efi? If so it had 2 fuel pumps (low pressure in tank, high pressure on the frame rail) that together provide too much pressure for a carb. For the carb conversion was a pressure regulator added? Or was the low pressure pump in the tank used alone? Can you hear a pump running back by the tank? There would also have been a filter along the frame rail originally that could be clogged if it is still there.