Yellow Posted April 2, 2018 Report Share Posted April 2, 2018 To start: I have a 1973 620 l16 4 spd. A few years back I ordered a long block from the east coast somewhere, after my stock l16 took a dump. According to who I ordered it from (ebay) it was a l16 out of a 74 510. So I swapped The pan and threw it in, been running fine since. A few years pass as I got more and more into the scene, I looked a little harder into what type motor I recieved. The head that is on the new/installed motor is an A-87. From what I have read those only came on l18's. How can you tell a 16 from 18? Also, what are the chances it is a peanut head? Is there anyway to determine if it is a peanut or a 18 without tearing it down? Compression ratios perhaps? Thanks in advance. Quote Link to comment
flatcat19 Posted April 2, 2018 Report Share Posted April 2, 2018 Block stamp is on back right of block below #4 spark plug. Unless you have a really good boroscope, you can't determine head without a teardown...at least for the A87. I have a 79 620 that showed up at my house a few weeks ago. I was excited to have an L20B to dink around with. Opened hood to find just an L16...but a mystery A87 head is attached to it. Quote Link to comment
Crashtd420 Posted April 2, 2018 Report Share Posted April 2, 2018 Also you might wanna try to see what type of pistons the motor has.... I forget what the stock L16 has for a dish in the piston but the original 210 head is only 38.5cc In the combustion chamber... The a87 head open chamber is 45.3cc Closed chamber 41cc... so either way you are lowering the compression ratio.... And I believe stock compression ratio is around 8.5 to 1, so it will be lower than that, Unless the pistons were swapped... ideally they put flat tops in it.... you should be able to see that through the spark plug hole.... 1 Quote Link to comment
wayno Posted April 2, 2018 Report Share Posted April 2, 2018 This head info is interesting to read. http://dimequarterly.blogspot.com/2012/02/tech-how-to-l-series-cylinder-head.html Engines with a lot of blow-by tend to leak oil everywhere as the blow-by blows out the seals, if you remove the oil fill cap on a running engine and can feel a steady flow of air coming out that hole from a couple feet away while it is idling then the engine is likely wore out, mine had so much blow-by it it made a wet oil spot on my hood with the hood up, I was putting over a gallon of oil a week in my engine when I finally retired it. Quote Link to comment
datzenmike Posted April 5, 2018 Report Share Posted April 5, 2018 Look on top edge of block just below the head directly behind the dip stick handle. You may need a wire brush. There were no L16s after '72 but there were L18s for end of '83 and most of '84 in the 610, 710 and 620 truck. Hopefully it is an L18. L16 and L18 are identical on the outside other than the block ID Quote Link to comment
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