spluttering still :(

[KEV 5 GT]

hi all I realy need help here trying to get this splutter out of the way for sunday is anyone around my area willing to help....she runs fine until comes on boost then splutters like a good un till 4500 rpm then she pulls ok im sure I can here like a hissing sound on the right side of engine bay ??

ive changed most things ie: plugs /leads/rotor/dizzy/fuel relay/rebuilt carb and gave a good clean all stock jets/

puzzled and sunday is coming stresss

[Mr Raider]

Was going to say maybe accelerator pump although carb's been rebuilt. Check all pipework as sounds like an air leak somewhere. :)

[KEV 5 GT]

ive checked what pipe work I can see and replaced with silicone there is a flat spot when first accelerate witch points to the acc pump but would this cause it to splutter as its always had a flat spot since ive had her