New engine break-in & oil question

[68jimmy]

I'm sure that this has been asked before but here it goes again...

I have a freshly rebuilt 350 and I'd like to know what you have all done for break-in and what oil you used, Should I use or stay away from a synthetic based oil during the break-in? How about for the long term, what oil recommendations do you have?

Thanks!

[Longhorn Man]

I have enver had a new (or rebuilt) engine to break in, but the industry standard is to run the engine to break in the cam (time and engine speed should be in your cam instructions) and then chainge the oil and filter, then drive easily for the first 500 miles, not keeping the engine at one particular RPM for long periods of time, chainge oil and filter, and then let her rip. You should not use synthetics for this.
For the long run, synthetics are way better than dino oil. There are still some ppl who say that "if we've used dino oil since the begining of time, why should we chainge?"
lap reports don't lie. We took a well used but good running late 80's Caprice Classic, 305 with throttle body injection...did a lab test on the oil when we drained the oil. Did two oil chainges with Mobile One synthetic, and then ran it 10,000 miles. Drained the oil, sent a sample to the lab, and the results came back cleaner than the 3000 mile old dino oil.
With a carb engine, it probably isn't a good idea to run 10,000 miles between chainges since the much less presice metering of fuel does result in oil dilution, but 6,000 miles should be perfectly safe.
On a slight side note, probably the best oil filter per dollar spent would be the NAPA filters, they are made by WIX. The Fram that so many ppl think is top dog, is actually junk. If you were to cut one open, you'd see what I'm talking about.


All this info comes directly to me from the oil lab we have dealt with at the shop for over 10 years, (since the shop was established) and is a fully indipendent lab. Many local race teams including IRL, drag, and motor cross race teams use this lab, along with most of he fleets that we maintain. All the info here has been proven to me with either documentation, or actually performiung the test myself.

[bigjimzlll]

use a decent 30 weight dyno oil(non-synthetic) for break in of cam and ring seat..I throw a bottle of EOS(GM engine oil suppliment) for the break in. After the cam and rings are broke in I use mobil 1 synthetic...some weight 500 miles..then change to synthetic

[Quagmire]

http://www.bobistheoilguy.com/

learn yourself