What is a good "little hotter than stock" spark plug for y blocks?

While the Autolite 45’s gets the job done for most Y’s, the Autolite 46’s would be the next step up for a hotter spark plug.

Lorena, Texas (South of Waco)

That is what I am running, is Autolite 46, gapped a little big. I am starting to carbon foul the plugs, wondering if hotter plug might help.

If this is new, then something is probably not operating correctly, carb, timing, compression (worn rings), etc..  If it is not new, then it may not be tuned correctly.  Make sure things are in good condition and in proper tune before trying a hotter plug.



Lawrenceville, GA

The engine is fairly new, ( two years) the compression is good, the timing is dead nuts. I'm running  Mallory electronic ignition I assume it is working right. Now as far as carburation goes that is where the problem more than likely is. I have three Stromberg 97's on an Elderbrock manifold. with the old wore out 97's the plugs burned just right, a nice golden brown. This past winter I put all new carbs on, I am having a heck of a time getting the mixture to run a little lean. I have gone from .045 to .043 now to .041 jets and the air/fuel mix screws are barely screwed out. I certainly don't want to burn holes through the pistons, I am getting a little frustrated and not real sure what to try next. By the way how would you check an electronic ign. system to know that it is putting out the correct voltage and that it is all working right? I'm sure it is a simple solution, something that I have over looked, so any advice from you guy's will be greatly appreciated! THANKS

Do the strombergs have power valves in them like the holley 94's ?  My engine measures 283" and I'm running .53's in all three carbs. It sounds like you're running way rich. If it has power valves my guess is they are leaking. If it has power valves are the end ones removed and plugged? I'm running a 6.5 power valve.

  Dennis in Lititz PA

From what I could find, they come with 45's, and a 65 power valve. If you're running the pv on the end carbs, I suspect Dennis is on the right track. Also, what jets and pv in the old units. They probably leaked a bit of air, especially under light load/high vacuum. So new units should be a bit leaner on the jets.


miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

All the previous suggestions are good ones.  Let me add that as a general rule, anything with carburetors likes a 0.035” spark plug gap or less.  The extra big spark plug gaps are typically reserved for fuel injection and lean mixtures.  The richer the mixture or the higher the compression, then the less the gap must be.
 
I had some recent issues with a new set of Edelbrock 94’s being too lean on an aggressively cammed three deuce 272 which was fixed by reducing the idle feed restrictions in the new carbs from  0.063” to 0.052”.  Your problem sounds to be the opposite.  If you have the new Strombergs, then it might be prudent to block off the end carbs and start working with each carb singularly in the center position.  You may have a problem with a single carb which will be difficult to isolate if running all three simultaneously. Running the carbs one at a time may help to better isolate the problem if its a problem with a single carb.

Lorena, Texas (South of Waco)

The Strombergs do not have power valves like the Holley 94's




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