Suggested Engine oil. Synthetic. vs Conv.

[Scotty.92]

I know this has already been placed as a topic but still need help choosing. I have a high mileage motor (323,800km. Roughly 201,000mi). Not sure on whether the previous owner used synthetic or conventional. Also wondering about weight and brand of oils. I do know that the flat tappet camshaft in the 350 TBI (All FT cams) require added ZDDP. I am wondering about what oil I should use, and what type of oil. I believe OE rating was 5W-30. I live in a climate with cold temps during winter, thinking the 5w-30 would be better than 10w-30.

I know that low ZDDP levels with cause excessive wear on the cam lobes because it does not have the additives needed to operate between the two metal surfaces, unlike hydraulic rollers that uses a roller than a flat tappet. (Unfortunate enough to find that a Pontiac 400 we are building for a Trans am had been using the wrong types of oil. Needless to say, a few cam lobes were about half way gone, and not much of a peak to the lobes either as much as a circular shape. Complete rebuild anyway with new Comp Cam 262XE)

I am just concerned about using synthetic oil if it has not used it before. Any help would be greatly appreciated! I know I always hear people using. Valvoline VR-1, Royal Purple, Mobil 1, or AmsOil.

(Also wanting to do complete tune-up of the motor. I have just bought spark plugs, air filter, oil filter, dist. cap/rotor. I am thinking I will need fuel filter, and plug wires yet. Anything else?)

 

[94Cheyenne]

A good can of sea foam,

I put a 1.3 can in the vaccum when running, and let sit for 10 minutes, a 1/3 in the gas tank and 1/3 in the oil when i have ~50 miles left on my oil change.
Great stuff....
As far as oil, Honestly I use Quacker state and cheap fram oil filters and it's gotten me to 220k w/o problems. whatever you use, just change at 2500 miles and stick to it.
also take into account that if you do a lot if idling (like in traffic) that that also counts as parts of your mileage.(not linear but hourly)

just my 2cents. I don't know much about sny V. conv. enough to say much and i'll let someone else chime in!

 

[Ruger_556]

I just switched to Royal Purple (102,500 miles on my truck). Didn't leak before and still doesn't, oil consumption went from 1.5 qt/3,000 miles to zero noticeable usage, gained 5 psi oil pressure (5W-30 same weight as before), and the truck previously had a bit of a rattle when hot (balance shaft possibly... common on the 4.3). The noise disappeared entirely after the first 1,000 miles. What more can a guy ask of his oil?

Do some more reading on ZDDP levels... This has come up before and I think greatwhite was the one that came up with the answer last time although I could be wrong.