Best 5 speed conversion for '68 4.2 FHC?

[sbxke]

I'm sure that this topic has been discussed many times but I just can't seem to find the thread! Any ideas?

[politeperson]

I read quite extensively on this subject and my conclusions from others experiences seem that it is very expensive and a bit hit and miss. The conversion also seems to involve quite a bit of engineering.

Quality from the aftermarket suppliers seems a bit variable, and parts supplies going forward questionable. Some suppliers have come and gone.

As an alternative I fitted a locking XJS 2.88 differential and retained the 4 speed all syncro box.

The car seems to accelerate as well as it did before and motorway cruising has been transformed.

It has a wide speed range in all the gears.

At the end of the day, the car only weighs 1,3000 kgs and has a torquey 4 litre engine to pull it around, so I wonder if it needs and more gears than the original designers intended. Another example of an en excellent car with only 4 speeds is the early 911 (930) turbo. More gears seem unnecessary here too.

The other advantage is that these XJS units cost a few hundred pounds and the whole job can be completed in a day.

[abowie]

If you look at the "similar topics" section below you can read some of the other threads.

[1954Etype]

I have a 2.88 diff and always thought it was the best upgrade and it is if you cruise a lot. Now having driven all of the different ratios, l can confirm that (in my opinion) the 3.07 is the way to go. The car retains the sparkle and the high revs are bearable on motorways (but most people avoid motorway driving whenever possible). For the ultimate though, a 3.31 matched to an E Type fabs box is the way to go. If l had the money, l would do it in a heartbeat (got the diff lined up).