What type of oil should i use in my 78 400

Whats up fam, first time im doing an oil change in my truck. What type of oil should i use for my 400 6.6L?

 

10w30 conventional or synthetic blend, if high mileage (75 - 100 k ) Valvoline Maxlife is an excellent oil. Hope that helps.

 

If your Summers are typically hot all day long (and IIRC Garden Grove is that way), you probably should use 10W-40, then 10W30 for the Fall, Winter and Spring.

 

I'll just mention again, current oil does not have the zinc chemicals to protect the flat-tappet cam that will be found in the 400 motor. Include some zinc additive with each oil change.

 

Garden Grove CA. ? Or different state.

 

Garden grove my brotha, gets pretty warm in Cali in summer time. 90s and 100 at times.

 

Thanks everyone, ive checked them out and will defently get one of the ones named here. Might even do a bit of additive, ill look into it deeply

 

Back and forth between TX and CA most of my life, grad of Los Alamitos HS. You want warm come to TX. Bad choice of words, give it a few minutes and you might even get all four seasons. Temp in the OC hits 90 you are running for the bar or nearest AC with the ocean breeze coming through every day in the early afternoon. Anyway after the ramble, where you live 10 w30 .