Mike, check out amsoil . They've got 75w90 GL-4 synthetic for $7.80/qt.

I ordered 4qts* of that, 3qts of 80w90 @ $7.40 and 4oz. of LSD additive. $70 shipped.

*The DSM calls for 5 7/8 pints, but my notes tell me I put 3 1/2 qts. in last time.