Baffled by Gearbox variety for conversion.

sebby

Forum User
I recently posted looking for a 280 ZX 5 speed manual box for an auto to manual conversion on a 72 LHD 240Z. I understood this was a good box for conversion and would fit without any major issues.

I wanted a straightforward conversion using the original propshaft, crossmember and 3.5 diff. I understand the 3.9 diff is said to be preferable. I hoped to use the original centre console. I’m a steady driver not looking for a race or drag car.

So far, no one has offered to sell one but I have been offered a variety of others though specification is lacking.

One is described as a 5 speed dog leg 63A which came from a 510 Racecar having been mated to an L24. I understand this is an early box, prob pre 72. Sounds like it may have had a hard life.

Another is described as a rebuilt but untested 3 piece 5 speed box with prop and the seller advises using the 3.9 diff.

The third option is a standard 4 speed box which I suspect may be OK with the 3.5 diff considering it would originally have had a 3.4 in the US.

Has anyone advice on the best option to keep things simple without the fuss of shortening propshafts, etc. I’ve read so much about problems getting parts to connect either within the bellhousing or at the output shaft.

I don’t want to buy, or be sold, a pile of parts which won’t fit.

Thanks.
 

Mr Tenno

Digital Officer
Staff member
Site Administrator
Probably best just waiting, setting up eBay alerts and putting wanted ads on the various Facebook groups - 280ZX 5 speeds and 3.9 diffs do come up occasionally but you might have to be patient as there's a lot of American cars coming over to Europe that people want to convert so they're in high demand.
 

johnymd

Club Member
I have had various boxes in all my zeds from 4 speed to 5 speed 240, 260, early 280zx and late 280zx plus s14 boxes. The s14 is massively different but the difference between all the others, for a car you plod around in, was very marginal. I actually really liked the 4 speed as it was very laid back and less gear changes.
 

Pondo

Club Member
I think Neil fairlineguy might have a 5 speed for sale? It’s on one of the other threads I believe.
 

sebby

Forum User
Thank you for your comments, all are welcome whatever your view. The more the better.

As much as I think I should hang on the problem with waiting for a 280ZX box is the demand/ competition. I’ve read posts going back many years were their rarity/ difficulty in locating has been talked about.

I have already placed ads in numerous Facebook groups and check ebay, Gumtree etc daily but it is yielding some results but not the one I want.

The comments by johnymd has made me consider the 4 speed as an option. I recall the wheeler dealers episode covering the conversion and I’m sure they kept the original Diff but can’t recall if they fitted a 4 or 5 speed. The S13 was considered, I can obtain one local but just too involved for me.

Maybe someone who has done this swop will find this post and comment. I need to make a decision and get back to these sellers.

I’m doing a guide just now on a Mazda forum for the MX5 Auto swop because there were so many unanswered questions before I started. That said, the MX5 has only a few gearbox and diff options. I wonder if there is a guide someone knows of that I’ve been unable to find which covers issues such as the centre console and the distributor. I’m quite happy to do a guide if one doesn’t exist.

Thanks again all.
 
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