I agree with Steve that a 10w-40 100% synthetic would do your engine wonders. Stay away from partial syns, they are a waste of money for the quality you want in your engine. Ive used Amsoil since 1975 and I worked for Amsoil Corp., so Ive seen the testing, bench tests, field tests, and tests done by fleets and individuals for over 25 years now. Its almost a waste of time to keep testing something over and over, so just use it and enjoy the benefits. You will find an increase in RPM, longer life, up to 25,000 miles or one year with filter changes at 6 months. Id also recommend Amsoil depth type filters. They are extremely heavy and filled with cotton fibers and bypass valve, they filter down to single digit microns, unlike paper filters that filter in the 25 micron range.
Dont stop with engine oil either, use the Synthetic gear oil in your tranny and rear end and synthetic grease on your axles.
The engines that folks are building up around this site deserve the BEST lubrication, not the cheapest, so dont spare a dime when it comes to the oil that keeps things running cleaner, smoother, longer.
If you'd like more information email me directly. I have many articles of tests done over the years to compare products.
Id also recommend oil anaylsis once a year to determine what is going on inside your engine. The results give you wear metals readings and any indication of antifreeze or other byproducts of combustion that might be detremental to your engine. For $25 thats great info. to have.
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