Interesting I say full synthetic. Who knows what they're [blending] in? Good Point. I never thought of it that way. Thanks; Mike
It'll run ok at high revs, just not quite as strong as it's capable of. The differences would more than likely only be seen on a dragstrip clock. MPH indicates horsepower and is what you look at to see if you did make any gains HP-wise. ET is an indicator of chassis tune and driving technique. Get a quality vacuum gauge and mount it as a permanent instrument inside the car. (Stewart-Warners 2 5/8" gauge is my favorite.) Plumb it to manifold vacuum - meaning, anywhere below the throttle blades. Once the engine oil is fully warm and you're in a safe place, floor the throttle and take note of the vacuum level as indicated by the gauge. If the carb is way small you'll show about 2" or so of vacuum. An about right size carb will show a little bit less than 1". Very few - if any - street driven carb/engine combo's will pull the vacuum gauge pointer down to the stop peg.
Having talked to reps from several oil companies (yes I know they may be biased since they work for the oil company but several diff. companies all said the same thing) synthetic blend oils are 1/3 synthetic, 2/3 regular. Also it's not the same as just mixing 1 qt synthetic and 2 quarts reg. there are other blending agents used to make them mix. Synthetic is soooooo superior to reg oil that 1/3 synthetic is still better than you need. If you run pure synthetic in a regularly street driven vehicle you are just wasting your money as there would be no difference in wear compared to synthetic blends. Now for race applications you want the best so by all means go for it. The big thing that ruins a motor is dirt in the oil. That's what makes it darker. Several companies have indicated that you could (if using synthetic oils) just change the filter every 2-3000 miles and add a quart to cover what came out with the filter and never change your oil again. Oil doesn't wear out. It just gets dirty. The only way for oil to wear out is if it is heated excessively but this much heat would no doubt burst your radiator hoses first. Newer cars oil change freqency rates are going to every 10,000 miles. (I have seen this on newer caddys and buicks) The biggest money making lie the oil companies have suckered americans into believing is that we need to change our oil every 3,000 miles. I have talked to employees at national conventions for one large oil company ( I won't name names because I don't want to get sued ) but they actually had a good laugh about it. In europe oil change frequencies are at much higher intervals than ours. Also note that the 3,000 mile interval in your owner's manual usually is in the "heavy duty usage chart" i.e. I only drive on dirt roads pulling a motor home uphill at WOT for hours at a time.
