Best plugs for carb'd roller

[forango]

Its a carb car, bit different for initial vs the efi stuff, what's it seeing full advanced, are you checking it with a decent dial back light or just setting initial, good way to see if the marks are off with a dial back light. How are you controlling the timing, threw the msd box or a vacuum advance or are you just running it locked with a stock type tfi distributor? Popping and farting on decel, make sure its got 0 exhaust leaks first, then Check rest of the ignition components. Backfire like bang, like can take out a muffler bang, definitely want to look at the carb too, might need a rebuild kit or rejet. A sub $100 wideband gauge with a good bosch sensor is a good investment.

Timing mark getting pretty close to the base of the strap. If your reading plugs for everything shut it off, pull over, swap a few of the old ones in and drive it back. Corners plugs if you don't want to do them all.

I have yet to check the total adevance because I haven't had a second person to assist with controlling the throttle. I am going to try and work that this weekend since I will have someone to help

The distributor is the steel gear verson for an '85 GT...The carb is practically new but it did sit for a while during the engine swap but still technically only a year old...Definitely an exhaust leak or two I am constantly chasing but nothing major

 

[forango]

Or a bad balancer.
I'd deal with the timing, check balancer, make sure 0* on the balancer is TDC on the #1 piston, rotor at #1 on cap..

The TDC, rotor and balancer shoudl all be good...I had to redo the distributor a few times to get it right but i will try asnd recheck it

 

[forango]

Base timing on most 302’s is around 12 to 14 degrees. You sure you don’t have the distributor off a tooth or a worn out timing chain? I just throwing stuff out but that seems to be a lot of initial timing to me.

I am not "sure" of anything. LOL...I bought the engine already built but unless the builder screwed up the timing chain shoudl be solid..the engine only has about 10K total miles on it

 

[forango]

I appreciate all the replies and info btw...Seems to be something I will be chasing for a while and potentailly never get just right...The bitch is when this thing is in the powerband at WOT it screams and moves out

 

[Noobz347]

I have two sneaking suspicions to add to what the dudes have said above:



Lean pop - The white residue on your plugs indicates [lean] to me. This can cause a pop on deceleration.



I would also suggest that a leaking injector can cause this too but you're carb'd so, fuel may be working it's way into the engine when fuel is supposed to be [closed] off.

 

[Rcdgl]

autolite or motorcraft plugs, gap for stock spec and try that.

 

[forango]

I think I figured out an area where I can do a nice WOT hit and immediately shut it down and pull off to check the plugs....Here is my question:

Is it ok to pull a couple plugs while the engine is that hot or am I risking damaging the threads in the heads?

 

[AeroCoupe]

Very little risk and I only say that due to the odds are you will burn yourself.

 

[forango]

Very little risk and I only say that due to the odds are you will burn yourself.

I likely will find a way to do that. LOL

 

[forango]

Ok so I found a spot to do a decent WOT pull from about 25--80ish...These are plugs 1 and 5

 

[FastDriver]

AFR looks good to me. Couple plugs want a tad less timing... others are on point. I'd pull a degree, but I err conservative.

 

[forango]

AFR looks good to me. Couple plugs want a tad less timing... others are on point. I'd pull a degree, but I err conservative.

Technically these are only 2 plugs..the front corners...not sure which one looks perfect and which is a touch off

 

[HotFox]

Blue strap means to much timing! I would replace plugs (atleast the blued ones) and pull atleast 2 degrees, test again. A carb will be inherently rich, put cats on if you want it to smell better.
Tune for leanest cylinder...