SPARK plug gap for 360 cu in...350 HP

I have been using NGK 7938 plugs for a while in my 79 360. These are V-POWER plugs and I had good results with them so far. I was wondering if the spark plug gap I am using is ok since I seen quite a few different ones lately.
JG

I forgot to add that the engine is not really stock. It has an Edelbrock 650 cfm carb, stock ignition. 1.6 rather than the stock 1.5 rockers, a higher performance cam on which I have no numbers but it is not very over stock and it is .030 overbore.

What gap are you runnng now?

I’m using a champion plug gapped at 35 on my 340. I’m thinking of using the same plug on my barracuda but gapped a bit higher as I am running the ignition system off a 99 360 truck. But I will start at .035 and work my way up.

Hey J-G with the stock ING run 0.035 you could go up to 0.040 if you wanted to . JMO .

Thanks for the info

As to the gaps; you should run as much gap as you can until the ignition coil can't jump it any more under max load.This will give the highest voltage, with the longest duration, and hopefully the most amps. Amps is what you actually need. But, your engine only needs enough gap to never misfire at full Load. Any more is  just taxing the system.
Most stock coils will jump .035 without any struggle.
Most aftermarkets will jump .045  no problem.
The most powerful and most reliable Coil I have ever had and still use is the Square top Accell Supercoil. I wonder sometimes if I couldn't make a welder out of it.
It jumps .080 at WOT  no problem. But You need a special plug to go that far. If you try to gap a standard plug that wide, the side-electrode will be at a severe angle, and the spark will just jump to the nearest surface.
So then, I gapped my standard Champion Copper cores to .045/.050 This has proven itself to be adequate even with a poor tune.
Do not mix  coils and amplifiers. If you have a CDI System, you need a CDI compatible coil.Don't use a standard coil on a CDI-amp or vice-versa. Most CDIs are designed to fire about 525 volts into the coil, and that transistor fires it in there, like lightning, so the coil has very little time to saturate.  A standard coil may not respond properly.
A CDI coil is wound differently and has fewer turns in it, to work with the 525 volt input. If you run a regular Kettering Ignition, which only outputs about 7.5 to 14 volts depending on the Ballast used, the coil will never work to it's potential.
Do not buy a coil that says it works on both, because in all likelihood it will, but not to it's best potential. That Accell I talked about is a Kettering.
At 350hp you don't need much of a coil or gap to get the job done. If you are not experiencing misfires, your system is A-ok no matter what gap you are running.

At Cruise rpm and load-setting, sometimes a wider gap can be beneficial, as, you can lean out the AFR a lil, without misfires. This will save you gas.  You can save even more gas by pumping her full of Ignition advance.
At a cruise rpm of 2240@65 mph, my HO 367 likes at least 56* degrees for best fuel-economy.
How much does yours want?
That's easy to figure out. In N/P, Rev up the engine to cruise rpm +/- 100 and keep her there, while simultaneously pulling in advance, with out respect of how much. Every time you pull in a few degrees, the rpm will go up. Keep doing that until the rpm no longer rises.  Now check your timing with a light at that cruise rpm. Subtract 3* for the no-load factor. This number is what your engine wants.
Whether or not you can give it, is another story.
Now
Rev the engine back up to cruise rpm, and diddle the mixture-screws for highest rpm.  If the rpm increases  more than 50 rpm, put it back, and repeat. When yur done, that is the best it's ever gonna be with the current parts. And with the current parts, the potential for hiway fuel-economy will also be the best it it can be.
Can your 350hp/360 engine make 25mpgs@65mph?
I dunno about yours but my 330hp/367/ manual-trans could and did; and even more...... with overdrive, lol.
Now, don't forget to put everything back to where it was before you started cuz if you detonate the skirts off it, I ain't buying you a new engine...... lol.
If you need help setting it up for fuel economy, PM me cuz I don't come here often. If you do PM me, bring your Compression-Test results. My 68 Barracuda made 32mpgs @185psi cylinder pressure with a final-drive ratio of 1.97 .. This cannot be done at 135psi.

This spring I started by regapping my plugs at .040 and this amplified a whole process which started late last summer. I ended up having to replace my 35+ year old coil with a new one. I also brought back the gap to .035 but unfortunately the coil did not last long. I would not be surprised that it could handle the .040 now as it runs like a swiss watch now.

What coil are you running? On my Magnum 360 I'm running an accel standard size coil and I'm running a 045 gap no problem. On the Demon I have a MSD blaster coil with regular single ballast and I'm running a 040 gap for years but I have not tried to increase the gap on that car, but so far no problems.

Good luck. I've only ever had one coil go bad personally, but when it goes your screwed!