I have a rebuilt 312 with 1500 miles on it. Noticing right side rockers near firewall more noisy. I have not pulled the valve cover to check for oiling issues. Lash was reset after 100 miles from being rebuilt. Engine builder thinks he needs to reset the lash again. Is this normal or is there another problem why I am getting rocker noise?

Yes, it's normal to check, adjust lash after break-in. Why didn't you pull the valve cover?

Had some life things get in the way and started up after 5 months.

Some tappet noise is normal for solid lifter engines.  Only by removing the valve covers and doing a preliminary visual and then a valve lash check will you get an idea of what’s wrong if anything.  Potential things that can be taking place to make excessive noise are:

1. Incorrect initial valve clearance adjustment
2. Rocker arm adjuster(s) simply backing off
3. Rocker arm stand bolts are loose
4. Incorrect pushrods with a smaller than stock ‘cup’ that are trying to ‘wear’ in.
5. Lack of oil causing premature wear at the pushrods, rockers, and rocker shafts.
6. Cam lobes or tappet faces going away

Engines that sit for extended periods of time are prone to sticking valves due to old fuel.  It’s not unusual for sticking valves to allow the pushrods to jump out of place.  Fuel that is ½ year old or older is going to be highly suspect and especially if the vehicle is being stored in a non-climate controlled area.

Lorena, Texas (South of Waco)

If you didn't pull the valve cover, I assume you didn't pull the distributor to rotate the oil pump to get the oil flowing. After sitting for 5 months, how long did you have to crank the engine before it started? Do you have an oil-pressure gauge or just a light?

Ted, thanks for the info. I will get some fresh fuel in this weekend and check with covers off.

It started after 10 seconds. Just have idiot oil pressure light.

I use non ethanol fuel. Will it degrade slower than ethanol fuel? Just curious.

Thank you also 55blacktie

"Just have idiot oil pressure light."

You need to verify oil pressure. 

"I use non ethanol fuel. Will it degrade slower than ethanol fuel? Just curious."

It will not degrade as quickly, but will overtime. If it smells like varnish ... 

Today's gasoline (even E0) is not the same product as was available in the fifties and sixties.   

Were the rocker assemblies rebuilt?       

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Yes rocker assemblies were rebuilt.

The rebuild depends on the quality of parts, machining and assembly - 

http://forums.y-blocksforever.com/Topic167745.aspx

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