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tune up



I'm doing my first tune up on my '67, including flushing the radiator. Any suggestions on oil and filter brands or specs, or any other valuable info?
For an everyday use oil filter you can't go wrong using an AC. Not only is it original equipment but if you cut them apart you fill find much more filter media in the AC than the popular orange one. There is also the option of using a high performance filter like the K&N, AC heavy duty or others. They filter down to a finer micron but also cost considerably more. Not really necessary on a street driven car that gets serviced every 3000 miles or 3 months like it should.

As far as oil goes any major brand name will give good service. I use GM Goodwrench, which is Mobil, because my wife brings it home from work at a discount (no, not five finger discount). I don't know how fresh your engine is but new cars use 5w30. In fact that is what they put in my Olds Ciera with 204,000 miles and I don't use a drop between the 3000 mile changes. For a more performance engine you could use 10w30 in the cooler months and 10w40 in summer. If your engine has some miles on it 20w50 would be a good choice for the summer months.

For tune up specs use the recommended AC spark plug for your engine set at the recommended gap unless you are having a fowling problem in a cylinder or two. In that case an extended tip or hotter range would be an option. The good high perfomance GM points set hasn't been available for some time and I can't recommend the foriegn made points that they sell now. Get Accell or Mallory points. Install them at .018 gap with the rubbing block on the top of one of the distributor cam lobes and then adjust the dwell to specs with a dwell meter when it's running. Don't forget to coat the cam lobe with the lube supplied with the points. Use a quality cap and rotor from the same manufacturer. A cap with brass terminals is better than the service aluminum ones. Also check your distributor for end play. If there is too much it will cause irratic spark and the rotor may even contact the cap terminals breaking a few things. Look at your old ones for evidence of contact. You may need to remove the distributor and add shims under the drive gear. Set your timing to specs and then when the engine is warm advance it a couple degrees at a time while test driving it just to the point where slight detonation (pinging) can be heard. Then back it off to where it stops. That will give you the best performance. If you experience a lot of pinging at part throttle you will want to get a vacuum advance unit with a stiffer spring. The easiest way would be to get an aftermarket adjustable advance unit. Then you can stiffen it up with an allen wrench to eliminate pinging.

If you are into judging plug wire sets with the proper date codes are available. If not there are several good companies making high performance wire sets. Hot Rod Magazine did a test of a bunch of different wire sets a few months ago. Dig that up for some good suggestions.

I'm assuming that your carb is in good working order but if yours uses a divorced choke thermostat mounted on the manifold and connected with a rod it is a good thing to replace the therm every few years. Under normal use thay are only good for 2-3 years before they get weak. Go to Paragon (listed in the Portal) for these.

All of the actual specification numbers will be found in your shop manual. If you don't have one they are available at any of the Corvette parts houses and you should get one before proceeding.

If I have missed anything I hope someone else will chime in . Good luck on your tune up. Nothing better than a sweet running Corvette.

Thanks very much, Tom. BTW, does my car have a radiator drain plug?
As far as I know it does. May not have a petcock in it though. I'm thinking on the back passenger side of the lower tank. Probably hard to reach and see but it's been a while since I had a '67.

If you're going to do a thorough flush, pull the hex head drain plug on each side of the block just above the pan rail - these are the ONLY drains for the water jackets around the cylinders, and hardly ever get touched - an amazing amount of corrosion and crud collects down there. Don't be surprised if nothing comes out when you pull the plugs - just stick a piece of coathanger wire or a scratch awl in the hole to break through the crud, and coolant will POUR out. You have to do both sides, as they're not cross-connected. When you put the plugs back in, use some anti-seize on the threads so they're easier to remove next time.

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