gspfunk

I'm sure I'll get disagreement, but if it's just stock or mostly stock, Castrol GTX 10w30 will work just fine. I've used it in my cars for years and love it. If it were a newer motor I'd go w/ sythetic, but on an older car w/ stock internals, I wouldn't mess w/ it.

biglg

Since the guy i purchased it from lived in CA, he said he was running 20w50 synthetic. I switched to 10w30 synthetic blend, i live in MO. I changed it the day I got the car. Would that change have anything to do with the pressure? Also, once you run synthetic, arent you supposed to stay synthetic? I have heard that, but dont know if it is true.

5.0stanger

I run straight 30 wt in the summer and store the car in the winter with 5w 30 or 10w 30. The 30wt works well/ I live in Michigan and deal with the same temp issues.

groundpounder

gsp, I've done some research including talking to the boys at Eagle. Those guys said the the Mellings HV is the way to go. Can't get much of a better recommendation than that. I have a 7 quart pan, which makes the HV make a little more sense, and the pump came with a heavy duty drive shaft.

biglg, I think you should run 20W50 in your car. With that many miles, your tolerances are a little wider and having a thicker viscosity will help you. Synthetic or not is up to you. And run a good filter, not just a PH8A.

biglg

I jsut cant believe that 20w50 isnt to thick for a basically stock mustang. I thought 20w50 was for high peroformance, track cars?

Do I have to stay synthetic, since that is what has been in the car? Can I go to a non synthetic, I have been told you shouldnt/cant do that.

groundpounder

If I had to go one way or another, and like I said the choice is up to you, I would go synthetic. Especially since it was in the engine before.

And 20W-50 is not too thick for an engine with 140K ticks on the clock, but if you want to run 10w-40 you would be allright.
High performance/track cars typically are set with higher/wider initial tolerances to allow for greater expansion due to higher heat as a result of operating at higher compression, greater RPMs, heat exchange due to higher octane fuels, forced induction, nitrous, etc. I'm not saying you have those kinds of tolerances, but your tolerances (piston-to-wall clearance, maybe ring gap, end play on your crank, lash in the timing chain) are all greater now than 140,000 miles ago. By staying in those wider gaps longer, thicker viscosity oil will help maintain the integrity of your overall lubrication throughout all operating temperatures.

Hope this makes sense.