best type of oil for 71 340 engine

[340wedge]

I live in a warm climate and use AMSOIL 20w50 Z-rod which contains Zinc.

 

[toolmanmike]

I live in a warm climate and use AMSOIL 20w50 Z-rod which contains Zinc.

Ya, zinc goes without saying in a flat tappet engine. If you run a roller you can run pretty much anything. Weight depends on the bearing clearance. I keep it simple and run Valvoline 10/30 conventional and some zinc additive.

 

[RustyRatRod]

Another magnificent thread revival.

It happens. lol

 

[toolmanmike]

I'm surprised there's only 27 responses in 10 years. Folks are tired of answering the question! There might be some wrong answers but no right answer. LOL

 

[ir3333]

Unless it's a big hp build or you're racing it, Penzoil 5W30.
..but nobody wants to hear that

 

[70aarcuda]

Walmart Supertech 10w-30

 

[mullinax95]

I really like the Joe Gibbs Driven oil. 10w-30 is what my engine builder told me to use.

 

[Gator]

In my Hi Performance 340 I am running Pennzoil 10W-40 with a can of STP at every oil change and 20k miles later engine is still running strong with no problems....

 

[Brooks James]

I’ve had outstanding results with Mobil 1 for over 30 years.

 

[Nat]

i ran royal purple 10-40 xpr synthetic for 9 years on my 70 340 never a problem when torn down to add new alu heads and check **** out at 7,000 mile it looked new inside almost no wear on any of the parts . i added zzdp the first 3 oil changes nothing after that ,
let me add every engine is different no idea how yours was built , just stating my experience