Jump to content

Possible L16 to L20b

Recommended Posts


I have a chance to purchase an L20b motor.  It doesn’t have a carb or distributor.


I currently have the stock L16 w/4 speed in my 72 510 sedan.


i know I need the L16 oil pan, oil pickup tube and mounts.  Would the L16 manifolds, distributor and carb work with the L20b? 


Im just looking for a bit more pep without going over board.  Should I consider building it?  If yes, any recommendations and part list?


Should I consider it?



Share this post

Link to post

L20B from what? 


All 20Bs have 6 bolt cranks and flywheels so your 5 bolt L16 flywheel won't fit. Better get the L20B flywheel with it. Speaking of flywheels..... truck L20Bs have 225mm diameter clutches but if the L20B is from a car they are 200mm same as your L16. Not saying to use the L16 clutch, but if it comes with the 200mm clutch, your L16 release bearing collar should be compatible and everything should bolt together. If it's from a truck try to get the release bearing and the collar or you'll hav t to buy one. It will be matched to the larger 225mm pressure plate.


L16 distributor will work on an L20B but try to find a proper pointless (breakerless) matchbox EI distributor and coil for it.


L16 oil pan, pick up and dip stick will work on the L20B.


An L16 carb will work after a fashion, may need jets changed slightly larger .


If the L20B  has a U67 head you can swap the intake and the exhaust manifolds but must drill two 3/8" holes in the head to allow coolant into the intake runners. Just use the intake/exhaust manifold gasket for a '75-'77 engine NOT a '78-'80,  to locate these two holes just below the two pair of intake ports. In this case you will need the coolant return line that joins the intake coolant to the thermostat by-pass down across the front of the engine to the lower rad return line inlet to the water pump. Just use the L16 parts


If a W58 head, the holes are already there and use a '78-'80 gasket set. Why? the W58 has round exhaust ports, the earlier U67 have square ports. The coolant lines and the bypass are already there. Carry on.


L20Bs usually have a clutch fan. It may stick out and cause rad clearance problems.... your L16 water pump will fit just fine, but if the clutch fan clears, keep it.


L20Bs use a differently positioned crankcase vent pipe to the PCV valve. The hose should be close enough to fit the L16 intake.


L20B blocks are 3/4" or 2cm taller than the L16. So closer to the hood and the 510 exhaust at the engine will be higher by this amount. If the L20B comes with the L20B engine brackets, this may sling the engine lower? 'Course the pan would then be lower but not necessarily 3/4". You'll have to check. If no L20B brackets the holes in the L16 ones can be ovaled to lower 1/4"? It may not even be an issue. 

Share this post

Link to post

Thanks for the response guys.  From what I can see in the pic, it’s looks as though the exhaust manifold is square where it bolts up.  He also said the tranny is auto.


im assuming I’d have to track down a flywheel as well?

Share this post

Link to post

Yes. They are six mount bolt and can come in 200mm, 225mm and even 240mm pressure plate and clutch sizes. The flywheels are all basically the same and the pressure plate mounting bolt pattern determines what clutch will fit. You can easily measure across the friction contact area to identify it.




This is a 200mm PP and clutch but a 5 bolt for an L16/18 but you get the idea. It doesn't matter much what size you get, you might not have much choice, but what ever size you do find you will need a matching pp and clutch and a release bearing colar to match. Some clutches are sold with the collar included.

Share this post

Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

By using this site, you agree to our Terms of Use.