65 Valiant 273 - What oil?

Our fleet finally has a Hamb friendly car but I have a question about it. When you first start it up in the morning it sounds like it has very low oil pressure almost to the point of knocking for 5-7 seconds then it goes away (also the oil light doesn't always come on). It currently has 15w40 in it, should I run 10w30 or 5w30? Or perhaps synthetic? The reason for my concern is that on my other DD (an OT 70's mini) oil pressure gets up to 70 almost instantly. Any suggestions would be appreciated.


Here is a pic for those who are curious:

 

Brad penn

 

synthetic is horrible for your internals I have heard awesome things about brad penn and also vr racing oil

 

What grade should I run? 10w30? 5w30? because I'm guessing 15w40 is too thick for it.

 

I'm not sure about what weight oil it should be (probably 10w30, but someone else please correct me if I'm wrong).

I just bought a '65 barracuda with the 273 under the hood, and first thing I did was put a bottle of rislone zinc additive into it, since modern oil doesn't have enough zinc (zddp) in it.

Make sure you put an additive into whatever oil you run (look on the oil additive and make sure it says zddp on it).

 

15W40 is NOT too thick for that car
Here is Chrysler recommendation from the owners manual for 1965;
SAE 20W-40 When temperatures are consistently above 32°F

Do you have an oil pressure gauge? Or are you guessing it is low based on a noise? It could be a sticky lifter.


and this "synthetic is horrible for your internals" is the funniest thing I have heard all day. I've been running Synthetics for over 30 years in everything from daily drivers to my race cars, and I have yet to have "Horrible" things happen the the internals of my motors. Maybe he meant your body's internals if you drink it

 

Unfortunately it doesn't have a gauge just the idiot light, which doesnt always come on when you first start it (ie just turning the key to the acc position) so its just based on the noise when I first start it for 5-7 seconds.

 

Might just be a lifter or two bleeding down, if they are hydraulic. Didn't a lot of the 273's have solids?

 

I believe its solid, as they didn't put hydraulic on LA engines until 68.

 

Small block Mopars are noted for doing that when they get older. A shot of STP will lube the bottom end til the oil hits. For the most part, just ignore it until it gets real bad, then an overhaul will be needed. You could put new shells in it now if you want to quiet it down.

 

If thats the case why was it less noticeable when it had 10w30 in it?

 

ALL 273's are solid lifters he needs to adjust the lifters