340

Hello everyone, I have a 1966 plymouth barracuda that came with a 273 automatic two barrel. I did a recent build on a 340 and rebuilt my 18 spline automatic as well. I need to go into detail about everthing i did so you can help me with my question so you know what i got. I built this motor to be as close as possible to 1968 . 340 block bored 30 over, keith black kb243 pistons eagle rods, comp cams magnum muscle 20-309-4 or 268ah-10, early j heads with big valves updated seats and seals and springs from comp cams. I have brand new carter avs 4636 with choke as well. I installed a true 21/2" manifolds down to the back exchaust from tti. also running bone stock intake manifold. also running my stock 273 manifolds with a thick copper gasket along with gaskets in my rebuild kit , no leaks fits well. running a stock distributor with pertronix points conversion along with a high voltage coil no ballast. My compression is just back of 10 to 1. I had my 273 crank turned and balanced to match my transmission. i have drove this car some maybe around 150 miles or so off and on. heres my question four of my plugs are black four are kinda getting there tan, two plugs on each side is black lol. I haven't taken the carb apart yet. I also have moved the timing up and down to see how much before rattles and how much it can take for easy starts. no difference on plugs either way. I always found a 340 love some advanced plenty of it, it doesn't seem to waqnt quite as much. Is my carb delivering more fuel on one side?