Swaping drivetrain from '71 Series 1 to '73

[MaximumHP]

I'm planning to swap in the entire drivetrain/suspension from a '71 series 1 to a '73 body. I understand there are differences, but I should be OK doing this as long as I use all 71 drivetrain parts. The body mounting, etc should be the same, correct? Or might I run into problems?

Also, will the dash fit as well, I noticed the mounting by the trans tunnel was a little different.

[Arne]

Two things come to mind off hand. A manual transmission '71 came with the early Type A transmission. Most people have to make allowances for the shift lever location when going the other way. I'm pretty certain that the larger opening in the '73 tunnel will accommodate the early tranny OK, but you might want to verify that.

The other thing is a bit more complex. The '73 had the improved differential location. If you use the parts from the '71 you'll need to use the '71 mustache bar and driveshaft, and you may have clearance problems with the diff limit strap.

Since the '71 location is clearly inferior, I'd try to stay with the '73 location if I could. You will still be able to use the '71 diff, but you'll want to use all the diff mounts from the '73, as well as the '73 driveshaft. That would be a much superior setup, IMO.

[MaximumHP]

OK thanks Arne.

The '73 has a hacked away tunnel already, plus I have a 5 speed I could use so one way or another I should be OK there.

OK, so the mounts on the '73 body should be the same, except the diff strap might not be in the correct location. I have all the parts for the '71, so I'd be swapping everything.

At the moment I don't have any components for mounting with the '73 set-up. Eventually I can swap over to parts from a 72 parts car, but right now that's not really possible unless there's no way the 71 stuff will fit. (This is sort of temporary, not finished product configuration)

[Diseazd]

Why are you doing this? Most people go the other way to get rid of the driveshaft angles ( gets rid of the rear end vibration ).

[Arne]

So I'm guessing that you have a bare '73 shell, and a complete—but probably rusty—'71 car. So yes, if you move everything over you should be OK other than the limit strap. You may have to remove it (if present) to get the diff mounted in the more forward position.

As for the dash, I believe the early dash will bolt in, but the wiring, switches and gauges are different. You'll probably want to use the wiring and gauges from the '73. Or you could transfer all the electrical from the '71, including the wiper motor and all switches, but that's a rather large undertaking. The simpler route would be to reuse all of the '73 electrical in the '71 dash.

[MaximumHP]

Arne, Exactly. All I have that's '73 is the body. And all I don't have that's 71 is a body that's not rusted away. I have everything from the 71 gutted anyway, and have nothing else to put in there, so it's about my only choice short of buying more stuff, and I have more time than money. It might not be ideal, but I just want something that works for the time being.

Long term I'd like to repair the 71 body, but this will take me at least a couple years, so I'd like to have something driveable, even if not ideal, for the meantime if possible. Long term I could swap in the later diff mounting parts into the 71 when I get a hold of some and the body is finished.

[Arne]

So do you have the '73 wiring in the '73 body?

[MaximumHP]

Nope. Would be moving everything. 73 has doors, hatch, fenders, hood etc. but no or incomplete drivetrain/suspension and interior. So I'd be moving all drive train and suspension, and wiring/Dash. The PO of the 73 wanted the drivetrain/suspension as it was upgraded, and had the dash, but I didn't purchase it because I didn't really need it. Wasn't complete and probably would have been more work than just moving everything over anyway. I actually didn't know about the drivetrain differences until I got into this. Stumbled upon a thread somewhere on here about series one having different moustache bars and started looking into it. Live and learn I guess.

Do you know by how much approximately the later mounting moves the assembly?

[Arne]

The later cars have the diff mounted a bit more than an inch farther back, as I recall. So the '71 parts will mount it an inch farther forward than the strap is designed for. That may be enough to interfere with the diff casting as it gets larger.

Something to consider—to use the imporved mounting position I think the only two things you'd need to find from a '72 or later would be the mustache bar and driveshaft. The diff crossmember is the same, and I think you can reverse the front diff mount on the crossmember.

[MaximumHP]

OK, that isn't too complicated. I did hear a 240Z was in the local junk yard that I was going to check out this weekend, possibly I can acquire those parts.

Thanks for the help and advice, appreciate it.

Edited June 26, 2009 by MaximumHP

[MaximumHP]

Just an update:

The swap went fine, no problems. The diff stays small enough that the strap wasn't a problem.

[Diseazd]

Yeah, but is was tight as Hell wasn't it?