oil for 346 engine

[mr41cadillac]

what oil and weight to use in my 346 engine. its been rebuilt and has no oil filter. also should i use stp or what? i think 30 weight was original recommendation. im in southern ga temp. rarely gets below 28 degrees. john

[Bobby B]

John,
Hi. I've had good luck running 10W-30 Dino oil with a High Zinc content. Joe Gibbs, Brad Penn, Valvoline VR1, all good choices. Hope this Helps...
                                                                                                          Bobby

[harry s]

John, As Bobby mentioned the proper amount of zinc is the important thing. I used Valvoline VR 1 30 wt racing oil. I got it from Summit Racing.      Harry

[mr41cadillac]

thanks all ill get some john

[robert G. smits]

Royal Purple makes excellent high Zink oils and can usually be found at the Auto box stores.  Bob Smits #2426

[mr41cadillac]

after some research I found out that Castrol 10-40  oil has .12 percent zinc. its available at wal mart 5 qts for 16.97.  john

[Bobby B]

John,
I don't think Standard Castrol Dino Oil has the correct amount of Zinc needed for a Flat Tappet Motor.  1200-1400 ppm is recommended. Castro used to have an "XL" line of Castrol GTX specifically for use in Classic vehicles, but to my knowledge was only available in SAE 30W and 20W-50. Neither of those weights appeal to me as far as use in a classic vehicle. If you use an additive, it's recommended that it be heated and mixed with the oil or it'll stay suspended in the pan. There are many sources of reading regarding this subject.
                Bobby

[mr41cadillac]

bobby I meant to say  I bought the Castrol gtx 10-30. the article I read says it has .12 percent zinc . I read this on line in an article from hamb. however the bottle does not state it has zinc.  a little confusing. and ive already put it in john

[Bobby B]

John,
Castro GTX = 610 ppm Zinc. Content of Zinc plays a small role in the oil you choose as this should not be the deciding factor alone when choosing the correct oil for your car. And Higher zinc is not always better, it just means it'll stay in the oil a lot longer thru the heat/cool cycles as zinc breaks down in this process. Use whatever oil you like in your car, but please educate yourself regarding the products you choose if you want your classic car to last. Here's an excellent article that everyone interested in oil should read:
                                                                                                                                                                                         Bobby
http://www.chevelles.com/forums/13-performance/443674-zinc-myth-test-data-dozen-more-oils.html