I HAVE A '69 CAMARO WITH DZ MOTOR (302) IT'S BEEN RESTORED, INCLUDING A BLUEPRINT, SOLID LIFTER CAM. EVERYTHING IS STOCK, EXCEPT FOR HEADERS. THE HOLLEY CARB (4150) HAD #70 MAIN JETS WHEN I PURCHASED THE CAR. WITH THESE JETS I HAD NO HESITATION BUT, PLUS FOULED OUT IN ABOUT 1 & 1/2 WEEKS. I CHANGED TO #68 JETS, WHICH IS WHAT THE SPECS CALL FOR AND NOW I GET HESITATION AT LOW RPM BUT, THE PLUGS LAST TWICE AS LONG. I ADJUSTED THE TIMING AND THE HESITATION SEEMED TO TEMPORARILY DISAPPEAR. IS THERE A PLATINUM PLUG AVAILABLE (AC R43)? ANY OTHER THOUGHTS?
i wouldnt think you would need platinum plugs,is the carb. adj. correctly?,are you running a points dist,if so are points gapped and dwell set?if not what type ign. are you using?is the motor breathing ok(air filter)?make sure batt.has full charge and your ign.system is getting full juice it really sounds like your spark is not hot enogh to keep plugs clean.
I HATE,yes HATE!!!!,platinum spark plugs(they are hard to read)they willnot burn off deposits.The only reason to use them is if the plugs are difficult to get to...LT-1,ford v-10 van,anything with a coil per cylinder.