318 problems

[charger72]

I recently aquired a original 318 test motor(was told they only did carb/ingition work on it) from a school. The motor only has at least 300miles on it since its been around. But what i've noticed is that when im  sometimes driving and slow down to stop then speed up,  especially towing a trailer it seems like the lifters or rockers are rattling when I give it gas, but goes away at a steady speed or ideling. I took the valve cover over and it is very clean inside. couldnt smell burnt oil or anything. Im getting pretty good oil pressure too. I tried to time it, but the tab is missing on the block. What could be causing it? It doesnt smoke or anything either.

[Plumcrazy]

Sounds like it's pinging. The timing scale is on the drivers side of the timing cover if it;s a 70 or newer. What year is the engine supposed to be? 
Try turning the distributor clockwise slightly.  That will retard the timing.

[charger72]

I think it is a late 60's (68-69), I thought it  was the timming, so I turned the distributor back and it still does it, but if it turn it up, it gets worse. I couldnt find the timing tab anywhere, must be missing.

[Plumcrazy]

I think it is a late 60's (68-69), I thought it   was the timing, so I turned the distributor back and it still does it, but if it turn it up, it gets worse. I couldn't find the timing tab anywhere, must be missing.

It's probably pinging if changing the timing effects the noise.  Somebody could have made major changes to the compression ratio over the years.  Did you try premium fuel?
The timing marks are on the passenger side on the 69 and older engines.   But I don't remember if they are cast into the timing cover like the newer engines

[charger72]

I check on the passenger side of block and it said 7 69. I dont think they would of had a timing tab on the passenger side since that is where the waterpump outlet is. Could a exhaust leak at the manifold also do this?

[Plumcrazy]

I check on the passenger side of block and it said 7 69. I dont think they would of had a timing tab on the passenger side since that is where the waterpump outlet is. Could a exhaust leak at the manifold also do this?

That's the wrong water pump for a 69 engine.
Up to 69 the lower hose was on the drivers side and the timing marks on the passenger side.
They reversed that in 1970.

That's probably  a 1970 engine
The timing scale is cast into the timing cover on the drivers side.   A 1970 318 calls for the timing at TDC