Thanks for your answer

The engine run pretty cold, it never go over 180F, its short trips and before i take out this plugs(the day after) it have stand on idle for about 5-10 minutes when i check vacuum and ignition timing.

Thank you

Hi i tried with hotter projected tip plugs, ngk 6, one step hotter. No shining but rich maybe

I think your going in the right direction with a little warmer plug with a projected tip. the dry carbon is a rich condition. when you install the vacuum advance it will help clean-up the cruise a/f mix some. what carb/manifold and jetting are you using? you might take a magic marker and draw a line on the length of the plug where the clean spot on the rim of the plug is. try to see if that line lines up with the intake valve location.

My little 383/432 Stroker

Same cam as you

NGK 6

Angled Plug E Street 75cc Heads = 10.5 Compression - Same 200psi cold cranking on all eight

16 initial / 18 mechanical = 34

Factory HP Manifolds

Box Stock Edelbrock AVS 2 800 Brand new that I installed last year

Idle is perfect - Off idle perfect - 12" vacuum

However I just ordered some metering rods , plugs look a little rich

Hi, im using a Edelbrock avs2 800cfm, primary jet 104 and secondary 104, i go one step leaner with the needle from factory. Ok and whats the case if that clean spot line up with the intake valve?

Hi, nice set up. I have about 17-18 inch of vacuum on idle but also more cubes. It idles fine but when it stands on idle for a few minutes it starts to miss slightly, i dont really know why, i can see with the stroboscope light that the mark moves slightly when it miss. The mark is steady but it moves a few degrees off and on like that, it also showes up on the vacuum gauge when it miss it dops 1 inch, its not a steady miss but little now and than when it idles for ahwile.

You might consider using a ColorTune to see what's going on. It will tell you if you are rich or lean and if you run it on each cylinder you can see which one is misfiring.

Thanks for the tip

the clean spot is probably the intake wash. if you can take your finger and wipe it off clean then there may be some oil (the detergency in the oil will clean the rim up). if it's dry or gummy then it's the gas. it's just a simple check. I think your ok but sometimes you can't look at enough stuff. I wouldn't change that primary jet. maybe one step leaner on the cruise side of the metering rod, or perhaps the best thing to do is nothing until you've tried the vacuum advance out.

another thing is the idle jet. I haven't played with a 800avs 2 but I have played with the regular 800 avs and they do have a large, .040", idle jet. might play with the mixture screws a little.

Ok thanks! I will try it, im not loosing any oil that i can see on the dipstick so it would be surpricing if there is any on the plugs. I get the engine started today with the FBO distributor but the engine running no good with it, its blueprinted with 15 degrees vacuum advance at 15 hg/inch, i have 17 hg at idle but there was no advance at all so something is wrong with it. The engine go worse when i disconnected the vacuum hose but it not show any advance from vacuum when i check with timing light, i installed it at 16 degrees and with the light it shows 16, anyway somethings not right with it so i switched back to the msd pro billet.

Try adjusting the idle mixture screws with the motor warmed up or hot and adjust them in, one at a time, until it starts to slow down a tiny bit and back it out 1/8 turn richer and then go drive it normally for 10 to 20 miles and pull one plug and post a picture of that plug on here.
The reason I'm asking you to do this is to see if the idle mixture is to rich or the part throttle mixture is to rich
When it starts to miss at idle speed it is talking to you, it is either to rich drowning out that cylinder or to lean, maybe a vacuum leak
Good luck, stick with us, we will help you make it better
What intake manifold are you running?

Thank you! I will try that out and take a pic to show you here as soon as i can. I running a Edelbrock rpm dual plane manifold. I really appreciate all the help i get, thank you all.

there shouldn't be any advance at idle when using the timed port. manifold vacuum should pull it in but i'm afraid that may be too much. difficult to diagnose not knowing how the distributor was put together. as far as the carb idle mixture goes; carter says to adjust the mixture screws to the best idle/vacuum and then turn them in until the engine looses 25-50rpm. sometimes this works ok and sometimes not.

Thanks i will try to adjust the carb. The Fbo distributor is a blueprinted original Mopar distributor with restricted mechanical advance 18 degress and restricted vacuum advance 14 degress that should start to pull vacuum at 15 hg/inch, it came with msd conversion cable. I connected the vacuum to manifold vacuum but nothing. I tried to adjust the canister but it is locked in some way, so the distributor not working as adverticed

Your tune up is rich everywhere. I agree with the above about using manifold vacuum rather that ported vacuum for what you are doing. You don’t have nearly enough cam to require manifold vacuum at idle. That’s straight crazy.

If the distributor is curved correctly you don’t need (or want) full manifold vacuum adding timing at idle. Did FBO send you a sheet documenting the curve used, or did he just slam something together and send it out the door?

Either way, no way am I using manifold vacuum on the vacuum can for what you have. Second, you need at least 1 range hotter plug and you need to take some fuel away everywhere.

the more I think about this engine the more I think any kind of performance ignition curve is a waste. your engine, in my opinion, is more efficient than a stocker with that high vacuum. I have a stock 440 I run around in and it's not as efficient as yours. i'd 'bet it's doing well over 20"hg vacuum at cruise speed; maybe 22-24",...? i'd try a curve very similar to the original mopar performance electronic distributors. I think that would be a good baseline and go from there. hopefully your not using a loose torque converter (if this is an automatic transmission) or low rear gears (numerically high).

Thanks for your answer! I will lean the carb, it looks pretty rich. I did go down from Ngk 7 to Ngk 6, its Ngk 6 in this pic but its to cold too? Right now i dont any vacuum advance at all, im running a Msd pro billet, i wanted to run the FBO distributor but its not working as adverticed, he sent with a cheat how i need to install it, 16 initial, full manifold vacuum bring it up to 30 at idle at 15hg/inch and full mechanical 34 at 3200rpm but like i say its not working properly, the vacuum canister not advance anything and i have 18hg/inch at idle, something is wrong with it, the engine not running good with the FBO distributor with or without vacuum connected so i put the pro billet in instead.