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bigt80
United Kingdom
1052 Posts |
 Posted - 29 Jan 2014 : 09:54:37
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Hello Daniel & welcome to the forum.
Re your question; this is not a definitive answer, but as I understand it; boxes were same across range in the beginning, but different models had different axles - Rapier (std) 4.22 for example. When H120 came out they put higher ratio diff (3.89) and I have read that they also changed internal ratios slightly to reduce the 'hole' between 2nd and 3rd as the Holbay's engine was a bit 'peaky' and the power dropped off too much, even revving hard in 2nd - if you wanted to achieve claimed performance figures.
So, long-winded answer to say some internals were supposed to be different and a few bits made stronger, but all the boxes are pretty tough. I personally wouldn't be too concerned which one I had unless you're going for out and out performance. It is also said later cars did have higher ratio boxes as you suggest, but I think changed were only minimal.
Tricky part is identifying H120 box from Standard if separated from engine. The only way I've found and it is not 100%, is that on the casing, along with the date is a number - usually 6DA 21055: on H120 boxes the '6' is ground off. It's worked a few times, but not very scientific  .
I'm sure there are more knowledgeable than me out there, so hopefully you'll get some other responses. Cheers. G |
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1725 gearbox ratios
