It would depend on your build spec's. For a driver/cruiser with flat tappets,you'll want something like 10w30 Brad Penn,or you can use a conventional brand WITH the additional expense of a ZDDP additive .If you're going more radical,you'll want something heavier.If you're running a roller lifter set up,you can use off the shelf oils[no trick additive required].I,personally prefer synthetics because they last longer and adhere to parts better during extended shut down times that these sparcely driven cars see more often than not.