Hey,
I just fired up my new 400 small block today and was wondering what yall thought about braking in the new motor. I have a 76 malibu classic/Landau. Just installed a newly machined 400sb with 202 heads, RV cam, Gear Drive, High Flow water pump, Torker II intake and Holley 750 Double Pumper, Plus all of the other dress up stuff we really like. My question is, I've talked to several professional engine builder's locally and they all have different theories on breaking in the engine. Do you have any tried and true methods? Things I should look out for? ECT.?
I am already planning on running the engine for about 1/2 hour tomarow then changing the oil to remove metal shavings, then again at about 100 miles then a third time at 500 miles and finally not again until 2K miles. I had originally thought that I may just drive it friendly for the first 500 miles or so before I really stomp on it. That sounds like it would be really hard to do( holding back that is).

Use an oil with a high zinc content for initial run-in especially. Don't overheat it or run it too lean, or too rich. Do some load/no load cycles on it. On the first startup let it come up to temp as you set timing and carb, then let it cool down. Check for any leaks/noises etc. Check the oil filter and drain plug magnet for debris.