i got a 650 dp with modded 355 if you pull the plugs out some will be black some will look new i dont understand it,please help,mods are 355ci rpm intake dart iron egale heads 215 cc comp cam ex274 pro billet disribator hei,msd 6al with blaster 2 coil i have replaced the power valve and put new plugs and wires cap rotor,it still does it

 

Is there black smoke coming from the exhaust?

 

no smoke,its jeted 71 84,got my best ets with these jets

 

also has the 28 shooters

 

switch the plugs to different holes and see if the problem follows the plugs or is limited to certain cylinders. You might just have some bad plugs.

 

the plugs that looked new, i put them in the hole where the plug where black,now they are black,and the plugs that where black are now white after the switch

 

Whats your timing at? Are you running a vacuum advance? You sure its not oil rather than fuel? How long does it take for them to this?

 

timing is at 38* with no vacuum advance,its not oil black charcoal like,it only takes about ten min to do this