IVE HEARD YOU NEED TO CHANGE OIL EVERY 3500 MILES,..."
"Would this mileage apply to LT1 corvettes with full synthetic oil too? I was told full synthetic oil lasts longer to like 7500 miles or once a year."
most guys have heard that youll want to change the oil and filter in your corvette every 3500 miles or so, and thats certainly good general advice, but its not necessarily something youll need to do under some conditions, having the car sit days between drives, use of cheap oil and filters, dusty or wet conditions, extreme temps all effect the oils expected life span, use a good oil and a good oil and air and fuel,filter and you can go longer under some conditions.
synthetic oils don,t generally break down as fast, and have a higher heat tollerance than mineral base oils and getting 7500-10,000 mile on an oil change is something that can be done, but Id sure change the oil filter out every 3500 miles (once or twice durring that 7500,-10,000 miles because , its the crap like metalic dust and moisture that can get trapped & suspended in the synthetic oil that causes problems more that the oil breaking down when your talking about the better synthetic oils. you can generally take the dipstick out and look at the color,and crap suspended in the oil if you wipe the dipstick on clean white typing paper,if you check whats on the dipstick ,just after turning the engine off, after getting it up to operating temp by driving the car for 15-30 minutes, and get some idea as to the crud level in suspension, obviously if its filthy its best to change it out, but just getting dark in color means little because modern detergent oils are designed to hold some fine ash in suspension, so they almost always get darker with use, its the extra fine metalic crud, acids and moisture your looking for, and by the time they become obvious youll NEED an oil change, as the filters supposed to screen most of that out of circulation, and getting the oil up to 215F SHOULD burn out ther moisture.
just as an example
now I know Im not typical as I run a 10 qt baffled oil pan on my vette, I have a large external oil cooler, I filled the vettes engine with 9 qts of mobile 1 and a qt of marvel mystery oil,and used a extended length PURE 1 filter, but I changed my oil just before driving from miami fla. to a buddies house near colorado springs co. where I swapped out the filter before the return trip, where I drove to the corvette museum , in bowling green ky THEN TO THE SUMMIT STORE IN ga. ON VACATION THEN TO BILOXI ms and I had over 6000 miles on the oil (mostly higher speed freeway driving) when I arrived back in miami fla. about three weeks later, the oil looked almost new, it was only at the 7000mile point I changed it out as the last 1000 miles in local driving made the oil look worse that the previous 6000 miles
its worth the time to read thru both links
http://minimopar.knizefamily.net/oilfilterstudy.html
http://teamzr1.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=1774#Post1774
BUT I GENERALLY CHANGE OUT THE OIL/AND FILTER EVERY 3500-4000 MILES, JUST TO BE SAFE AS OILS CHEAP INSURANCE