I've never been very good at tuning (or spent much time at it) and am a little lost. Some advice on where to go from here would be appreciated. Here is the lowdown:
The engine is a new 408 with about 200 miles on it. It has a mild hyd roller cam (228 duration at 050), Edelbrock aluminum heads and Performer rpm intake, 10.5:1 dished pistons, Holley HP Street 750 vacuum secondaries carb. I now have the lightest spring in the carb, stock jets, NGK BKR7ES plugs, 15 degree initial and 35 total timing w/no vacuum advance hooked up. The engine runs fine with about 12" of vacuum at idle and runs at 195F. It seems to be pretty responsive down low especially. The car is a 4 speed.
I put the new NGK plugs in after about 100 miles. They are now sooty (black and dry) around the bottom of the plug and the electrode seems to have no deposits/looks bare perhaps dark brown. The car seems to accelerate fine, perhaps a little boggy which might be due to the light spring. When lifting off the throttle after a full throttle burst I see some smoke from the tail pipes momentarily. It's hard to tell the color but it looks very light.
I'm thinking that because the plugs are sooty that either the engine is running rich on the primaries (it's mostly just done some cruising) or the plugs are too cold. I had Accel 0786 plugs for the first 100 miles which looked pretty much the same when I took them out.(The Eddy heads take a totally different plug size than the stock heads)
Where to start? What is a good plug for this combo? I thought about buying a good O2 analyzer but they are little pricey.
