Every engine I work with uses a 5W-30 or 10W-30, unless it is a ford truck; they sometimes call for a 5W-20. What oil is suggested for the 5.0L 302 engine.(I am using a 4 barrel Holley Carburator.)
Thanks.

 

10w30 is the oil to use for maximum durability and it is what Ford spec'd on these motors originally, they only lowered it to 5w30 later on in an attempt to improve fuel milage.

 

Conanski is right on. For most applications 10-30 is what you want to use.

 

10W40 is normal. newer motors call for as low as 5W20 but i wouldn't use it on an older motor as it will go fast (ask how i know). i recently switched from 10W40 to 20W50 until i figure out where im losing oil through ( am not burning it ) on my ~'75 302

 

I would also run either 5-30 or 10-30.... 5-30 is just going to flow on initial startup much faster to the bearings. 10-40 is a little heavy for a fresh engine with say less than 80,000 miles.