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Discussion Starter · #1 ·
I have had the car for about a month and a half now and am still working through the general maintenance stuff. I put in new plugs, wires, rotor and distributor cap this weekend.

I was struggling to find the correct gap for the plugs and went ahead and did them at .045. As soon as I had the last plug in I saw the sticker right next to my head on the drivers side of the engine compartment that says to use .035. :spanked:

Mine is a 1973, 350ci, automatic, but the data sticker says the same for manual and automatic (.035). I went ahead and used AC Delco R44Ts. I figured why not go with what the car started out with when it was first made.

The car sounds good but has a tiny flutter / almost indistinguishable sputter every now and then when it is idling. I pulled all the plugs again (before I saw the sticker) and none were wet with fuel so they all seem to be sparking.

Granted, I do still need to tighten the header bolts and may need to replace the header gasket. I am a little nervous about that one.

The plugs I took out were all over the place from .040 to 050 but it was running pretty good before I did the swap.

Does anyone gap their plugs at .035? Does it make a huge difference or will the cooler spark make it burn any dirtier?
 

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Plug gap...

I believe you will be good using the Delco plugs.
I prefer the NGK plugs, but mine is NOT stock.
Hope this helps, jim
 

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I used the acdelco iridium’s on the 77' and the gap was .045, according to auto zone. They have been on there about 5 years no problem. I take one out every other oil change to check, they always look great. When you replace your header gaskets check out the one's from Mr. Gasket that are 5 layer aluminum gaskets. They expand with the headers to make a better seal. I used them with high strength lock tight on the bolts; I have never had a leak. That set up has been on there about 7 years.
 

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035 is generally recommended for points w/stock coils.

High output coil w/points or a stock HEI is 045

GM used some huge gaps like 055 on some 80s emission stuff but that's chasing hydrocarbon output more than enhancing driveability. Opening up past 045 is generally not recommended even with a hot HEI.

If it runs fine leave it be. Most cars like ours never see enough miles on a set of plugs to worry. If a guy changes em every 4 years it's probably not even 10k miles.

If the gap's too big cold weather driveability suffers more than anything. Big gaps in cold cylinders with cold fuel will result in sputtering under load. Again, not so much an issue with most C3s.

good luck with the car
 

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Discussion Starter · #6 ·
I went back in and gapped all but 1 and 2 at 035. 1 and 2 were the only two that had any build up on the old ones when I pulled them plus 1 is a real pain to get in to because of the headers. I left 1 and 2 at 045. I also found that I did not get 3 in tight :thud:. I think that explained the sputter :thumbsup:. Stupid mistake, but I am learning about going too fast and getting distracted in conversation while I am working.

So far I have just fired it up in the garage, but it seems to be idling really smooth / sounds great. If the rain holds off I should be able to get it out today or tomorrow at the latest.
 

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I went back in and gapped all but 1 and 2 at 035. 1 and 2 were the only two that had any build up on the old ones when I pulled them plus 1 is a real pain to get in to because of the headers. I left 1 and 2 at 045. .
If you take on a job it should be completed correctly.
Just because something is difficult is not a valid excuse to skip
it.
 

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Discussion Starter · #9 ·
I finished getting the new carb in last night.

Oh yeah, update: As part of my maintenance I tried replacing the fuel filter and have officially learned the value of an in-line filter. My old carb was pretty rough to begin with and when I pulled the nut that is supposed to hold the fuel filter in I found no filter. :thud: I went ahead and put the new filter in the carb and halfway through my test drive (which started out great) the car stalled and the manifold was covered in fuel. I have officially had my first OH S#*@!!!! corvette moment. :surprised (LESSON: Didn't have a fire extinguisher in the car but do now.) Wiped it off, limped it back home got some advice from my mechanic and ordered the new carb.

Looking at the old one last night the nut is clearly cross threaded. I know, I know, hand tighten, wrench for only the final quarter turn. But it is a lesson I am glad I learned. Looking back to another forum members advice, this is the "break it, fix it club" after all.

While I had it all off I figured this was also the best time for some new paint.

I am glad I did it all and found out just how easy it is, but was still a little frustrated by the money I had not planned on spending. That was until I was putting the carb back together and pulled up the pictures I had taken for reference, damn my engine looked rough before I started. I'll post pics in a new thread, but it looks excellent now. :partyon:

Next, I got to the moment of truth and the car started on the second turn of the key and WOW, I had no idea it could sound this sweet.:partyon::partyon: The money was worth it.

I have only had it since the beginning of March and this is my fist chance to take off from work and just focus on the car. I thought it sounded great before because it was the only way I had heard it, but it sounded nothing like it does now.:cheers:

I have a few more adjustments on the carb today, but I have to say I am pretty happy. So far I have done the plugs, wires, rotor, distributor cap, and carburetor. Top that of with some orange paint for the manifold and valve covers, black paint for the air assembly and it is looking and sounding like a happy vette.:D

To top it all off, I now have a 73' carburetor (Rochester Q-Jet) in the car instead of what I think was a 75'. Granted, it is 8 months late to be numbers matching but it's close enough for me. Some guys may say that is not a big deal, but I like it.:thumbsup:

I think the plugs are set right (045 for 1 and 2 and 035 for the rest). But what started with a simple plug question has evolved into a much larger project and more than a couple of good lessons. One of the key lessons being, the car WILL pick the project.
 
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