I have the wider scoop from Cobra Restorers. In the 15 years I have had the car, never a single comment on the scoop being different. Nor have I ever had a problem with fuel boiling and I have no spacers. What temp thermostat are you running? You might try just eliminating the thermostat and switchin to waterless NPG coolant which elimnates any and all hot spots and makes cooling much more even. Also runs without any pressure in the cooling system.
Alan Sorkey
CSX4083
Shreveport, LA