Checking the ratios, the V6 1st will be 3.95. That is even worse than the Type 9 3.65 
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But the diff ratio should be 3.9. So with the Redtop and some revs, ignore 1st and acceleration should be pretty good 
Yep, that's probably the best strategy. Also depends to an extent what tuning work you are going to be doing and how you'll be using the car.
Mine started out on Weber carbs and a 3.9 diff. Ported head and fast road cams peaking at about 7200 RPM, IIRC. Engine is a 2.0 Zetec, so a close match to the C20XE. Tyres are 195/50/15, so about 890 wheel revs/mile. It wasn't too bad in that config. Long motorway runs were a bit revvy but not excessively so.
I then fitted injection and gained a lot more flexibility at sub-3000 RPM and a bit more power up at the top end. The 3.92 diff ended up feeling a bit short after this, and 1st gear was certainly a complete waste of time.
I swapped to a 3.64 diff and first is still quite short (it always will be unless you change to a close ratio gearset) but it will just keep traction through 1st at full throttle with sticky tyres. Whether it's worth the delay incurred by a gearchange at circa 30 MPH I'm not sure, but 2nd will take it from just rolling to 60 MPH, and it will actually launch in 2nd gear. It feels slower off the line, but I wouldn't mind betting the time to 60 isn't far off and quite possibly quicker.
I do do a lot of touring, however, and it now cruises effortlessly at 80MPH at about 3600 RPM in 5th and does 38 MPG.
If I were more track focussed, I'd probably drop back to 3.92 or an even shorter diff, forget 1st gear, and have a closer selection of gears further up the speed range, aiming for 5th gear to hit Vmax at peak power.
My current setup is a long way off that - no way it's going to make 160 MPH in 5th.
You might want to consider if the Omega diff or a Sierra / Grandada diff is the best option. Both are pretty bomb proof and cheap as chips 2nd hand. I might put money on the sierra diff being a little lighter, but it does present more options if you get tempted by a LSD at a later stage.
Go on.. Put the Quaife box in it. You know you want to.
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Topic: V6 Manual gearbox query (Read 3321 times)