Hi, everybody. I have a 69 Skylark. The engine however was replaced with a crate 5.7L: casting number is 14093638.

If I'm in Southern California (warm all year) what's the best oil to use and where can I look to determine what filter to use?

Also, I have a TH350 tranny, any suggestions on fluid?

Novice questions, but I really appreciate the advice. Thanks!

 

There are several different options for what viscosity and type of oil you might use in the engine.
Having had many vehicles with older engines run in higher temps , (fleet) , SAE 15W40 always worked well for me. Newer engines have much closer tolerances and require a much thinner oil like 5W30 and some now even recommend synthetic oil.
Have you tried an auto supply store for the correct oil filter ? Many probably don't go back that far.
If the trans were new or just rebuilt you might have been able to try a synthetic trans fluid, but you might be better off just using Dexron III ATF which is backwards compatible and should be OK.