Jump to content

71 510 4 speed transmission mount


Recommended Posts

Well just to get this struggle out of my head, is the 620 mount and the 510 mount the same? According to eBay, the 510 and 620 are interchangeable, but since rockauto doesn't have a 510 part I don't know how to get a part number for it.  


Another quick thing is that the transmission will also be mounted on an L20B with an L16 clutch as opposed to the stock L16 with an L16 clutch. 


Thank you! 

Link to comment
  • Replies 23
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

If the clutch cover on the L20b is 200mm then use your L16 clutch arm/throw out bearing collar, if it is larger, use the arm/clutch collar that was on the transmission you got the L20b from, the clutch collar follows the clutch cover, not the transmission.


Also it depends on what year transmission mount you are talking about, early stuff is different than late stuff on the Datsun 620 truck.

  • Like 1
Link to comment

The '73 620 uses a same transmission and may match the 510 but '74 and on used a different transmission. Maybe....


To be able to use the L16 (200mm) clutch you will need an L20B 200mm (bolt pattern) flywheel from a car. Truck flywheels only fit the larger 225mm clutches) Further, if you're thinking of using a 5 bolt L16 flywheel on an L20B... it won't fit. If you have a 200mm 6 bolt mount L20B flywheel see wayno's post above.

  • Like 1
Link to comment
Link to comment

All L series 4 and 6 cylinder flywheels look outwardly the same. They can be broken down into 5 bolt to crank, for L16/18, and 6 bolt to crank for L20B/Z20/22/24, KA and all L series 6 cylinders.


It's the bolt pattern on the face and the contact surface diameter that determines what diameter clutch and pressure plate will bolt up to it. You should easily be able to measure across the wear or contact surface to identify them.


200mm is 7.87"..... L16/18 and L20B cars

225mm is 8.85"..... L20B trucks (includes the one year only '74 truck with L18) and KA and Z22 cars

240mm is 9.44"..... Z24 and KA trucks but will fit any 6 bolt crank.

Link to comment


I believe that is a late 620 mount(disc brake trucks?), that is used on the 720s also, I believe early 620s with the short 4 speeds used different transmission mounts, but I could be wrong, I don't know a lot about 620s, they made a lot of changes to that truck over its 8 year run.

Link to comment

wayno my info shows only one part number for the 620 trans mount. So it appears it was used with the 71B and the earlier F4W63L  I know the '73 uses a transmission almost identical to the 510.


I guess for $17 you could find out. The 510 uses a different number than the 620. So it may bolt to the trans but not the cross member?

Link to comment

Every 1972 620 I have ever seen looked exactly like a 521 except for the body shape, but I have concluded that other stuff had changed that is not so easy to see, like the transmission cross member, 521s didn't have a removable cross member, but I guess all the 620s did have a removable transmission cross member, so that may have been when they switched over to the better transmission mount.

I obviously have never owned a 620, but I like heads they came with, a nice assortment to pick from, a head for every application.

Link to comment

The 620 cross member simply needs to be rotated 120. This moves the mounting bolt holes farther to the rear for the longer 71B transmission.


wayno here is my trans mount for a 710. It uses the F4W63L, similar to the 510. Probably similar to the 620, 610 and the A10s that all used this transmission



Link to comment

So I can only assume this is the mount ..



Do you have the original that goes to the vehicle?

I am using that exact same mount in datzenmike s post..... it fit the transmission but not the metal mount in my 521.... maybe its the same deal.....

Might be something where you can drill new holes in the cross member and it will all bolt up....

I would be happy to get some measurements if your interested....

Link to comment

I think they will all fit the transmission OR all 71B will and all F4W63 and F4W63L will. Differences, if any, will be the mount to the crossmember bolt pattern.

That's what I was thinking.... don't know how that cross member is set up....

If the mounts are the same height it should be just a matter of drilling new holes in the crossmember

Link to comment

Height is another thing. Higher or lower affects the drive shaft angles and may introduce vibration. When I swapped a 71B 5 for my F4W63L 4 speed the back of the shifter was above the tunnel sheet metal. Maybe 3" higher using the 710 rubber mount. I had to section and lower the crossmember.

Link to comment

I'll make sure to post a picture tomorrow of the cross member, can't do so right now since the car is in a different location. Also i'll make sure to get the serial number of the transmission as to further help you guys out. I also believe if I am not mistaken, that the datsun roadster 4 speed has the same transmission but with a different bell housing. Which made me guess that the Chevy mount that the roadster owners use might also fit the 510 with the drilling of new holes in the cross member. As far as height difference goes, I don't see how some washers couldn't compensate the difference. 


Link to the Chevy transmission mount guide. http://www.311s.org/pmwiki-311/pmwiki.php?n=TechSection.ChevyTrannyMount

Link to comment

The 510 transmission is a F4W63. 26" long, speedometer drive on the rear left side. Two part aluminum case with bolt on oil pan with drain. Front case has a waffle pattern on it. Sedans have a slightly closer ratio gear set than the wagons.


I believe the Roadster 4 speeds are longer.


Washers won't help if the new mount is too tall. Generally if it fits (or can be made to fit) and does the same job... good enough.


Do you have the old one?

Link to comment

No, sadly the previous owner didn't give me the transmission mount, just the cross member. I have a roadster transmission laying in my parts stash and I thought that one had a mount I could steal from it and to my surprise it was also missing it. x.x  

He also forgot to give me the throttle linkage that hooks to the carb, and $100 for a new one feels like a lot tbh. :o

Link to comment

Well just found out that the transmission mount holes are the same, but the crossmember mount holes aren't. Which means the chevy mount works, but it will need to be adapted to the cross member like the roadster one too. To my luck the previous owner has the original 510 tranmission mount so I'll be picking it up tomorrow from him.

Also my flywheel has A67 written on it I believe. What does that mean? I also placed a 510 clutch on it to see if it was the same size as the matting surface and it seems to be spot on. The L20B came with a W58 head and I think someone on here said it usually comes with a 200mm flywheel.

Link to comment

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.