I purchased a 78 450SL with over 105,000 miles at an auction since it appeared to be in very good condition and won it for an extremely low price.

It was last registered 10 years previously and was unable to get a response from the previous 2 owners about its history.

I pulled the valve covers and the cams and both top ends were exceptionally clean with almost no apparent wear and the timing chain was very tight and appeared almost new. In addition, the oil tubes are very tight and no movement on them.

I changed out the antifreeze which looked and smelled like it was recently replaced and completed an oil change which was black but I did not find metal shavings or water; just had not been changed for awhile, then drained all the gasoline from the tank.

I pulled the plugs then shot some oil fogger in each of the cylinders. All the spark plugs indicated that the engine was running a bit rich but did not have any oil deposits on them.

So far so good.

So I checked the compression and here is the problem. As you stand in front of the engine on the right (drivers) bank the closest on to me is cylinder# 1. Now that we have proper orientation on this, I found that number 1 read 60lbs, #2 60lbs, #3 66lbs. Number 4 read 132lbs and then on the left bank number 5-7 read between 126-134lbs then #8 read 91lbs.

I shot a couple of squirts oil into #2 and the pressure shot up from 60lbs to 155 lbs.

I assess that I have a bad head gasket between # 1-3 and also worn rings.

Does anyone have another thought about my assessment?

Also, my question to anyone that has experience with the vehicles is that I do not want to pull the heads off to find their condition and wanted to see if anyone had an idea how to check the heads that is not hard to preform without pulling them off the block.

Also, does anyone have an idea where I may be able to buy a short block if the heads are good.

Any response will be appreciated. Thank you.