Iv'e heard good things from ex Chevrolet old school Mech.s and parts guys about GM's version of the Split-fire called the Rapid Fire plugs, haven't tryed a set yet, yes the 43 is the colder of the  two, 44 would be used if your car or truck did alot of stop and go city driving, and 43 would be used if you did alot of "rough service" type of on the job type driving.  anips2009-09-05 14:42:21

Don't go with expensive plugs like Split-Fire.  I tried them once and two of them cracked their ceramics within a very short time.  After I installed standard Champions (this was a big block Mopar, not a Vette), I had no more troubles.

I had a set of 44T plugs in it when I first started it. I switched to the 43T after seeing that they where recommended in one of my Manuel's. I think it idled better with the 44's, but it's hard to tell. My #6 cylinder seams to want to foul a little. That plug looks a little oily. The others look fine. Maybe a set of the rapid fires would help a little.

if your motor is original and not rebuilt and has some miles on it then problem with# six might be the valve seals being dried up or torn, you can replace them without pulling the head, but its a project if you do one you should do em all, a good winter job, if # 6 bugs you do do a compression and leak down test on that cylinder.

I checked compression about a week ago, all cylinders are at or within 1 or 2 lbs of 150lbs. So could be the valve seals. I should have done the leak down at the same time. What about plug gap...right now I gap them at 32...but i see some use 35. Would this help with fouling?

35 is standard for a point type ign. the smaller the gap the smaller the spark, the comp. looks good, think about maybe a hotter ign., Pertronic, HEI, MSD, where you can open the plug gap up to as much as 50 or more for now?anips2009-09-06 07:27:55

If it runs/idles better with the hotter 44s in it, that's what you should use. The slightly colder 43s might be allowing the #6 cyl. to load up. You may indeed have a bad valve seal on that cylinder. The hotter plug will keep the oil from fouling the plug like the 43 is doing.
I've always gapped my point-type Chebby plugs at a tight .30"...just too old school to change.
 A hotter ignition system would allow a wider gap, which helps greatly to increase the spark across the electrodes.
Definitely change all of the valve seals if you decide to do it. Lots of folks only put the seals on the exhaust valves, but I prefer to put them on both intake and exhaust. I also only use the "umbrella" type seals...not the goofy little o-ring types...those are pretty much useless, imho.


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Joel Adams
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Messing around with it this morning....I had a set of 44t's in the cabinet, so i put those in and increased my idle from 600 up to 700. Drove it 5 or 6 miles...stopped a few times to let it idle a while to see if it was going to try and drop that cylinder and it never did. Got back to the house and tried to idle it back down some but it tried to miss a little so set idle back up to 700. I'll see what happens the next day or so. I'll try to put a few miles on it and see how it does and also keep an eye on oil consumption. Joel would the smaller gap help this problem?

another problem is with the stock stamped rocker arms is when the valve opens the rocker it pulls the valve stem  against the valve guide and eggs out the guide causeing more stem to guide clearance allowing more oil  to run down the guide, worn intake guides and seals cause oil consumsion, because the incoming air charge pulls the oil into the combustion chamber through the guide.

Joe(anips) is right aboot the rocker arms pulling the valve off-center, especially on older, higher mileage engines...just the nature of the beast with regular rocker arms, tho...
Closing the plug gap up will not help with the oil fouling...it will most likely make it worse. If you close the gap a bit, and it seems to run better, then you prolly have a bad plug wire, or dist. cap terminal for that cylinder. The compression readings are fine, but a leak-down might point to rings that aren't sealing well in a particular cylinder...


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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

I put about 120 miles on this thing today...no problem with missing or anything, I think I'll leave everything set where it is for now. I'll keep my eye on oil consumption and probably when the weather gets bad I'll put some new valve seals in. What would be the up side of putting on roller rockers on at the same time. What are the benefits? 

because the the roller tip rolls over the tip of the valve stem instead of drag you get less guide wear, you don't have to buy the hi $ full roller ones unless you want to, I run Comp Cams roller tipped  rocker ball and nut type, they work fine for about $140 a set on a street engine.  anips2009-09-07 17:56:35