Thread: plug question

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Well first off this question is for my 350, bored .030 over, performer rpm intake, 2.02 heads, comp cam .490 lift, 286 int/236ex @ .050", 650 edelbrock thunderseries carb, msd 6al ignition with a 55k volt coil.
I recently had some carb trouble, Carbs fixed but fouled up my plugs decently, My question is what temp plugs to run and this is a bit off my main question but what should my timing be?

ac delco 44 or 45s, i personally run 45s, timing, approx 36 degrees total at about 3 grand. Try NOT to run above 40 total. Make sure its set with vacuum advance unhooked.

set overall timing.

ty for the info

.035, another question would u recomend the 45 over the ar10 rapid fire plugs?

Another thought - what do you do with the car most of the time? If it's like mine, and short runs, you may want to run a heat range or two up. If it's mostly long trips, consider down. Hotter fouls less easily, but burns up quick. I'm running two heat ranges up, but my driving is mostly low speed - parades, car shows, the odd cruise night - and I can gas foul plugs if I'm not careful. (Yeah, I know - fix the jetting on the carb... but it's set up stock, and the car never really liked idling around all that well).

I think the next hotter is 46 for the Chev. 45 is general use, and 44 is cooler/long trips. Somebody correct me, please, if I remembered that backwards...

A friend with a really high miles 350 in a pickup runs the hottest range for the engine, just to keep the oil fouling from happening so fast. He's waiting to change out the valve seals - thinks that's the problem.

Originally posted by SnakeHerder
Another thought - what do you do with the car most of the time? If it's like mine, and short runs, you may want to run a heat range or two up. If it's mostly long trips, consider down. Hotter fouls less easily, but burns up quick. I'm running two heat ranges up, but my driving is mostly low speed - parades, car shows, the odd cruise night - and I can gas foul plugs if I'm not careful. (Yeah, I know - fix the jetting on the carb... but it's set up stock, and the car never really liked idling around all that well).

I think the next hotter is 46 for the Chev. 45 is general use, and 44 is cooler/long trips. Somebody correct me, please, if I remembered that backwards...

A friend with a really high miles 350 in a pickup runs the hottest range for the engine, just to keep the oil fouling from happening so fast. He's waiting to change out the valve seals - thinks that's the problem.

you're wright on the no's, but the hotter is the longer tip. tell you friend no plug is gonna fire long in the oil , so he needs to get some anti- oil foulers and what they do is get the plug out of the oil and then they will last longer.

gotchya, just out of curiosity what happens if ur gap is too big?

High speed miss or worse. Can cause overheating, since you aren't getting all the power out of the fuel charge. Weak spark causes poor flame front propagation.

Saw this on my son's old Volvo. Gaps were .010 wide, and the car ran dirty for the smog check, started hard, lower fuel mileage, etc.

I screwed up and put a set of plugs out of the box into my 428CJ (thought I'd gapped them - gapped the other set on the shelf instead), and got missing and so on at about 3500. Fixed the gap, pulls to 6200 easy.

Originally posted by trenchdog73
gotchya, just out of curiosity what happens if ur gap is too big?

the spark is gonna jump the least resistance so if the gap is to wide, the more load(fuel and rpms)you put on the motor then more out of control the spark gets. it will jump everywhere except where its suppose to and cause rough idle and miss fire. when it does jump to the ground tab it will be to hot and burn the plug up to quick.

Keep in mind that this is just a recommendation, not a mandate; but, I'll have to agree with "71 Nova" about AC 44 or 45 heat range plugs. I'll go one step further and tell you that I use AC R45S or R45TS sparkers in all my Chevys from mild to wild depending on the requirement of the plug boss. I have a '79 Chevy 1/2 ton pickup that has specs pretty close to your engine and I run the AC R45TS plugs in it without any complaints. Those babies are always tan on the insulator shells no matter how I drive. I also run the same plug in my '67 Nova SS (slant plug 202 heads) and get about the same service as I do in the '79; but the Nova is barely streetable and certainly not an everyday driver. I think the AC plugs are a good bet for any Chevy V8.

Now about that timing, who knows? I usually push it as far as I can on the gas I'm using without getting into detonation (pinging, death rattle, etc.). I have the '79 pickup set at 8 degrees initial adavance and run it on the highest octane stuff I can get at the pump, which is usually about 91 or 92 in this part of Oklahoma. I run the '67 Nova SS at 12 degrees initial advance, but I use 104 octane avgas to satisfy it. I really don't drive it that much, so I can justify the use of such an exotic fuel. If I did drive it regularly, I would probably have to knock the initial lead back to about 4 degrees or less to keep it from pinging. And about total advance and knowing when it's all in, I never have known that in any detail on any of my engines. Mostly I time 'em by ear and seat of the pants, and only get the light out on the tough ones like Fords with EEC-IV.

Randy