I have a small block 350 in my car. Based on casting #'s (3970010) and engine code (V0806TXB) the block is from 1975. The cylinder heads (333882) are 1.94 intake, 1.5 exhaust and match the block. I know these heads are prone to run hot because they are lighter and have a double heat-riser but that is what is there for now. I don't know my compression ratio but I do not believe it is over 9.0:1. The previous owner was running AC Delco R45TS plugs but I was thinking of going down a heat range or two to a R44 or R43 plug. I don't have evidence of detonation but I though a colder plug could be safer. Also, what are thoughts on the extended tip plugs?
Spark Plugs
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I've never been a believer in the hype about this plug or that plug however I've gotta say I really like the e3 plugs. They are easy to find.
MolaKule
Staff member
Quote:
AC Delco R45TS
When I was racing Suburbans with modified 350's, I always ran the 45TS types unless the coolant temps got too high.
I did experiment with the 43 types but with the jetting on the 4-barrel carbs I used, I would see deposit buildup.
AC Delco R45TS
When I was racing Suburbans with modified 350's, I always ran the 45TS types unless the coolant temps got too high.
I did experiment with the 43 types but with the jetting on the 4-barrel carbs I used, I would see deposit buildup.
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How are the currant plugs burning?
Usually try to run the coldest plug you can without fouling. If the 45 is working and not getting burned up, then stick with it.
The correct heat range is one of the most misunderstood areas of performance engines. IMHO reading plugs is an art more than a science and without a good plug reader about all you can tell is what color they are. When reading 2 stroke plugs it approaches the mystical!!
I can do it but I can't take up the band width to explain it. I learned from a Champion Rep who came to race tracks in the 1960s and was tech support for Champ sponsored teams.
YMMV
I can do it but I can't take up the band width to explain it. I learned from a Champion Rep who came to race tracks in the 1960s and was tech support for Champ sponsored teams.
YMMV
Originally Posted By: Smoky14
The correct heat range is one of the most misunderstood areas of performance engines. IMHO reading plugs is an art more than a science and without a good plug reader about all you can tell is what color they are. When reading 2 stroke plugs it approaches the mystical!!
I can do it but I can't take up the band width to explain it. I learned from a Champion Rep who came to race tracks in the 1960s and was tech support for Champ sponsored teams.
YMMV
When I was a kid my great uncle(grandpa's brother)was into a racing scene. He'd take me with him. He would tune a fresh engine by reading the plugs.
One pass up the track,shut if off,pull the plugs and then adjust with new plugs.
I'm guessing the residue and colour of the porcelain was how he did it. I was just a boy.
Once I got older I came to realize every pass was for cash. He had a 455 rocket in a 67 chevelle. When that car started the sound wave could almost knock you over if you were behind the car.
The correct heat range is one of the most misunderstood areas of performance engines. IMHO reading plugs is an art more than a science and without a good plug reader about all you can tell is what color they are. When reading 2 stroke plugs it approaches the mystical!!
I can do it but I can't take up the band width to explain it. I learned from a Champion Rep who came to race tracks in the 1960s and was tech support for Champ sponsored teams.
YMMV
When I was a kid my great uncle(grandpa's brother)was into a racing scene. He'd take me with him. He would tune a fresh engine by reading the plugs.
One pass up the track,shut if off,pull the plugs and then adjust with new plugs.
I'm guessing the residue and colour of the porcelain was how he did it. I was just a boy.
Once I got older I came to realize every pass was for cash. He had a 455 rocket in a 67 chevelle. When that car started the sound wave could almost knock you over if you were behind the car.
Unless you have done internal engine modifications, such as raising the compression, hotter cam, etc. The AC R45TS or equivalent from Champion or Autolite will be correct plugs for your engine. The use of a colder plug could cause fouling under light engine loading as the plug tips don't run hot enough to burn off contaminants.
Was the carb rejetted? E10 will run somewhat leaner than non oxygenated fuel. This Not to say you will be lean but you might be. Most of the guys running aftermarket carbs are jetted too rich.
Originally Posted By: MolaKule
When I was racing Suburbans ...
There's a statement that I never thought I'd see. Growing up, we always had at least one Suburban. Is there a story to be told?
When I was racing Suburbans ...
There's a statement that I never thought I'd see. Growing up, we always had at least one Suburban. Is there a story to be told?
+2 on that, 3put.
K5 Blazer Yes, Suburbans?
WTH?
K5 Blazer Yes, Suburbans?
WTH?
MolaKule
Staff member
Originally Posted By: ARCOgraphite
+2 on that, 3put.
K5 Blazer Yes, Suburbans?
WTH?
Long story, but back in Kansas we had a Burb Racing Club with classes for Modified 350's, and 454's.
I usually ran a 355 with a high lift CompCam, Headers, High Energy Ignition System, LSD Auburn's, non-cat Dual Exhaust, Modified 700R4's, and high flow induction systems with 4-barrel carbs.
Ok, so we looked like beached whales coming off the starting lines, but it was fun.
+2 on that, 3put.
K5 Blazer Yes, Suburbans?
WTH?
Long story, but back in Kansas we had a Burb Racing Club with classes for Modified 350's, and 454's.
I usually ran a 355 with a high lift CompCam, Headers, High Energy Ignition System, LSD Auburn's, non-cat Dual Exhaust, Modified 700R4's, and high flow induction systems with 4-barrel carbs.
Ok, so we looked like beached whales coming off the starting lines, but it was fun.
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Originally Posted By: ARCOgraphite
Was the carb rejetted? E10 will run somewhat leaner than non oxygenated fuel. This Not to say you will be lean but you might be. Most of the guys running aftermarket carbs are jetted too rich.
Yeah, but does he have a feedback style carb? Those would compensate if they were functioning correctly.... Which they often didn't and that is one reason early smog cars were hated.
Was the carb rejetted? E10 will run somewhat leaner than non oxygenated fuel. This Not to say you will be lean but you might be. Most of the guys running aftermarket carbs are jetted too rich.
Yeah, but does he have a feedback style carb? Those would compensate if they were functioning correctly.... Which they often didn't and that is one reason early smog cars were hated.
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