heres the deal normaly run valvoline 20-50 in 1978 460 mudbogger will it hurt to change 2 10-40

 

http://www.mobiloil.com/USA-English/...t_Engines.aspx
Here is an interesting article on engine oil. You might want to read this before making any changes. If it were me, I'd go with a high quality diesel oil or synthetic.

 

i use DELO 400 a great motor oil and if you want syn get Rotella 5W40 syn

 

A little off topic but if you have a little knock in your motor or a ping to quiet it up replace one litre or quart for you Americans with one transmission fluid. Done this for years to my 351m

 

ya it also is super high in detergent so it makes it really clean inside too

 

0W-30 or 5W30 quality synthetic. It WILL free up power and it WILL protect just as well. Most people run way too thick oils. You can step up a grade as the motor wears out.

More info than you'll ever want to know about lubrication of any kind, well okay maybe not any kind... . I'll let you decide for yourself........
http://www.bobistheoilguy.com/