Thanks for all your replies. I am fairly clued up on the various versions of T5, and I know that I need to source a ‘world class’ unit (although I think that definition was Ford’s, and not an official Tremec classification). I have a copy of some tables of a selection of part nos vs application, with data on torques and ratios, but this does not cover UK cars such as the TVRs.
Thanks also for your suggestions of suitable T5 suppliers, but unfortunately, living in the UK makes it more difficult to source one of these economically (on a budget). I am sure there are several companies in the USA/Canada that can provide what I want, but the cost of shipping by far prevents it being the best option.
So I was hoping for some guidance on what I can find available locally. I have noticed recently that the TVR units are becoming available at very affordable prices, and I think the gear ratios are quite good, but I have not yet got details of the dimensions, so I don’t know whether it would make a good unit for the Tiger. Does it look right to you? Is it like the AMC units?
As a couple of you have mentioned, I could adapt a stock Mustang T5 if I was prepared to do some mods to the tunnel (not clear what this actually involves), but on the Tiger I prefer to keep mods to a minimum, such as a slight relocation of the gear lever position; a shift to the right would be easy mod to do and would be beneficial for my RH drive car.
On the topic of suitable ratios, there seems to be quite a variety of opinions. Theo considers the 3.35 first completely unsuitable, whereas jloganjr actually recommends it!! Personally I like the high ratio (2.32) of the Toploader, so I will be looking for the nearest I can get to that, which is probably going to be 2.95 (as in the TVR, and the 5th gear ratio of 0.8 would give 29.9 mph per 1000 revs which I think is fine).
(BTW: Jloganjr, what is a s-10? Does it look like the TVR one I picuted in the link? But I think a 5th ratio of 0.68 is a bit too high (36.6 mph per 1000 revs)).