3.5 v8 power problems

well the old girls running 3.5 v8 put a new ignition amplifier on her/ found an old vauxhall amplifier lead that was compatable bugger paying £20 for two bits of wire tuning guy was,nt much help, said it was the diaphrams tickovers a bit lumpy but she settles down but power seems to be down holds back when running past 3000 revs and she developes a rattle when low down in third gear but theres nothing when ticking over temp seems to wander sometimes between a quarter and half way but she,s been rebuilt done about 750 miles so is she due for having things checked over and tightend down now any thoughts would be appreciated:welcome2:

is it carbs or injection

stromberg carbs manuel choke decided to rebuild the buggers after the tuning guy said they were flooding and diaphrams were no good. just find the same problem as before turned out to be ignition ampilfier but also replaced leads plugs and cap, rotor arm and the base plate and contact unit inside the distributor