fitting gti radiator to clipper 1.8

Hi does anyone know if i can fit the larger gti radiator to my mk1 clipper 1.8. my clipper is running a tat hot ive changed the water pump,rad,and thermostat,It still seems a little to hot and after long journeys i get pre ignition when turning off and slow start up as the fuels boiling in the carb so im told.Any help guys

yer you've got heat soak from you exhaust manifold if your getting boiling fuel.
do you have a heat sheild?

a bigger rad isn't going to make much difference. (i thought gti rad was the same size as a carbed rad)

Intresting...so is this to do with an aging manifold or is it a design flaw?