10w30 or 10w40
 

Which weight is best for ford engines, Im running 10w40 rite now

10W30, as it says in your owners manual, for your engine.

10-30

Motorcraft 10-30 to be specific. (According to the manual)

For your engine, in your climate, I'd run Mobil 1 10w40 until October, and then switch to Mobil 1 10w30. For a stocker, 10w30 is fine.

Take care,
~Chris

Chris: just wondering why you would run 10w40 in a motor that is stock except being .030 over?

Because it's far from stock. :)

I'll let him share the details.

:)

Take care,
~Chris

Ok, even if it is far from stock, why the heavier oil?

Because from what he told me, the builder that put that engine together had racing in mind, and I'm willing to bet that he was a little more generous with the bearing clearances than a person would have with a stock engine. Not necessarily loose, but on the loose side. For example, if he was looking for a clearance between .0005" and .0025", he likely went with .0025". I don't know this for a fact, but I do know that the builder was experienced, and my experience leads me to believe he might have done things this way. If he did, than this engine will be happier with 10w40 during the warmer months, IMHO.

:)

Take care,
~Chris

Is there a reason engine builders go on the loose side with bearing clearances on race engines?

If you were running down the street, as fast as you could (let's say running for your life), would you rather be wearing Jordache-tight jeans or a jogging suit?

Take care,
~Chris

Thanks for the help guys as always. I do have the AFM Typhoon intake on the way. Ill get a chassis dyno when that is on. Next mods will be headers then 75mm or so maf to finish unchoaking the engine. Then ill go from there.

Hehehe, yeah you will.

:)

Take care,
~Chris