Ok. Ive searched and searched but i cannot find info on the differences in the 65-66 520 cab versus 67 and up. I know i have seen comments stating that the engine compartment is 3" shorter in the 65-66, but is that because the fenders are longer/shorter or frame length, the firewall sticking out more or the cab altogether is different? I am not sure. I have measured my 66 against my 71 and to me they look swappable. Is this true? Or am i limited to using only a cab from 65-66? Thanks ahead of time for any info on this.
65-66 cab versus 67 and up
Posted 08 October 2017 - 11:27 AM
All the 520 cabs are the same length wise, but the 1967/68 have a radiator core support for dual headlights, so that is significantly different, the engine bay size is the same on all 520s as far as I know.
Now the 1971 521 has a much larger engine bay(3 to 4 inches longer), fitting an L block into a 520 is a challenge, it will fit but it is tight, I re-routed the heater core hoses to the side in the cab and they exit to the side of the engine now, but I use the stock fan, if you use an electric fan setup you can likely have the engine slightly farther forward and have the heater hoses exit in the stock place, but it's still going to be tight.
The frames are basically the same, the front sheet metal is different on the 520, I would not expect a 520 cab to bolt onto the 71 L block frame and expect the stock engine to fit in it's stock location, the water pump fan will be where the radiator is supposed to be on the 520, but the 1971 cab will likely fit on the 520 frame, but the J13 block water pump fan will be 3 or 4 inches farther away from the radiator.
I expect you want a 521 engine in a 520, it is a challenge.
Where in Oregon are you?
Posted 08 October 2017 - 11:53 AM
What I have is a 66 single headlight 520 and I am looking for a replacement cab. I was told somewhere that the 520 cab from a 65-66 was the only option I would have however I have a 71 521 as well and when I take measurements of its cab it looks like they are the same. I could use a cab from say a 67 -71 just fine maybe. I haven't even looked at engine swaps yet as I hope to keep the j13 that is currently still running and in the 520.
Oh, and I am out in Saint Helens, OR
Posted 08 October 2017 - 02:54 PM
OK, so if you swap the 521 cab onto your 1966 frame the numbers will not match your 1971 Datsun 521 cab numbers/title, and you cannot use your 1966 title for the 1971 cab as that cab is not a 520.
Now if you know how to weld you could cut all the front sheet metal off the 520 firewall, and then cut the 521 front off the firewall and put the 520 front onto the 521 cab, then it will at least look like a 520.
Why do you want to do this, what is so good about the 521 that you want to put it on the 1966 frame, is the 520 real rusty?
Posted 08 October 2017 - 05:25 PM
That a cool ride. I like the extended cab and is that a unibody? Ive never seen that before.
I made that truck into what I wanted it to be, it's a lot of work.
So you cannot just cut the top off the 521 and weld it onto the 520 cab?
There is a 521 in the Vancouver Pick and Pull right now, if you know how to section body parts you could go get what you need from that truck and weld it into your truck/520, but you need to know how to do it, I did that kind of thing to make my kingcabs, but I am not a professional at doing that kind of thing, I make mistakes and then cut the mistake out and fix it, but you only have one try as 520/521 body parts are getting very hard to find.
Posted 08 October 2017 - 05:55 PM
Posted 08 October 2017 - 07:16 PM
Wayno would know more in this case, but I would look at removing it at the factory spot welds, not just hacking it off with a sawzall.
One jump ahead of the lawmen
That's all, and that's no joke
These guys don't appreciate I'm broke
Posted 08 October 2017 - 08:01 PM
Follow Wayno's advise. You did not search to hard as there is information in my 520 build thread. I would not replace whole cab unless you have to.
If you can find a 67/68 520 cab you could put your radiator support in this. and run the 66 grill.
Posted 08 October 2017 - 08:25 PM
No one is scrapping 520s anymore, and they want a fortune for projects, there is a 521 for sale right now for $250.00 but it has been on craigslist for a while and it is still there???
It sounds like more than just the top is screwed up as he is talking about looking at the frame for damage, I would have to see it myself but he is not just down the street, it would help to see photos of the damage.
That 521 is not going to last for long in the Vancouver PNP, I could hardly believe it when I seen it, I almost started running, but the windshield was broken.
Posted 09 October 2017 - 05:24 AM
Check the shifter opening in the floorpan on both cabs. The first half year or so of production of the 520 had the top-load transmission that was used in the late 320 pickups. Starting in about Sept 65 the transmission with stamped steel bottom pan was phased into the production line. The hole in the cab floor pan for the early transmission shifter is about 3-4 inches further forward compared to the later trany.
Posted 09 October 2017 - 06:16 AM
Check the shifter opening in the floorpan on both cabs. The first half year or so of production of the 520 had the top-load transmission that was used in the late 320 pickups. Starting in about Sept 65 the transmission with stamped steel bottom pan was phased into the production line. The early transmission hole is about 3-4 inches further forward compared to the later trany.
The dead giveaway there would be the hole by the gas pedal for checking the trans oil level. If yours is a early production 520, it may be worth it to try and fix the cab as those are pretty rare.
Posted 09 October 2017 - 10:46 AM
In general the 520/521 cabs(not counting in front of firewall) are the same, if the top or say back corner were damaged a 521 cab section could be sectioned in, but the early 520 doors have different door lock mechanisms than later 520s/521s, so if that area is damaged and that area becomes 521(sectioned in), then a 521 door might have to be used as the door locks/jams are in different locations and are different.
I have an early 520 with the hole in the tunnel and a different glove box door handle, but I have a 521 windshield in my truck right now.