I recently had Loyd over at RBT rebuild my ZF we changed the ring gear to the Euro type and the higher gear ratio is well worth it.
I know owners have changed ring and pinion gear sets and fifth gear sets, but I am unfamiliar with the term you used, "euro" gear.
Which gearset did you change out, and what was the ratio of the replacement set?
that is the standard ZF in Italy.
your clutch dont like it .
I assume you have not driven a car with the gearing? I forget sometimes what traffic is all about up hear in the outback, but it is a pleasure and not a problem at all, unless you live in San Francisco.
Engine's whit a lot of Hp the torque come's in whit 2000-6000 rpm.but are needed to come to the high speed .
Whit the high gear ratio , it's not relax to stop and go into a traffic jam.
When you choice is a lower HP engine you cannot drive's it really faster than 250km/h
1/2 hour of traffic jam is not unusual in my country.
I can only recommend it and I usually only shift up to 3rd or 4th on country roads (80km/h) and 5th is a blessing on the highway and keeps the rpm's down to about 3000 at 150km/h
Before, 1st gear was absolutly useless. 60mph was way too much rpm.
Now 1st is in a perfect range and 60mph is is just a little over 2000rpm. Perfect range for this engine.
How much did the 3.77 conversion set you back?
We do a new 4.0 ring and pinion wich is about 50% stronger than the original.
I collect the orders right now.
It is developed by a technical master with have done some transmissions for verry big companies.
I am looking for a 3.20 ring and pinion if anyone has a set.
My Bora has the 3.77 ring gear. It drives fine in traffic but drives even better at freeway speeds. We tend to drive pretty fast here in So Cal when there is no traffic. Since I never use it for work and such, usually my freeway drives are in the 80 mph range. It drives great. The Pantera on the other hand at 80 mph is not as good it revs too much for my liking. In my opinion since the engine is pretty powerful it would benefit from the 3.77 gear. Problem is the cost outweighs the benefits.
I‘ve just put in a 12 % longer 5th gear in one of my stock engined Panteras. This is the way it should have come as stock. Relaxed cruising, less noise and better fuel consumption is what you get. My other Pantera, which will have a slightly tuned engine, will get the 3,77 crown and pinion. In my humble opinion the Pantera can handle much longer gearing than we think. Donˋt forget to factor in tire circumference in your calculations.
A 3.77 may be more useful with a big cube engine. With a 4.22 in 5th, it's the equivalent of a 3.00:1 rear. A 3.77 in 5th is a 2.66. Kind of like a Lincoln cruising.
The trade off is that with a 2.20 first gear, you only have a torque multiplication of 8.2. For performance usage you need that number to be between 10 and 11.
Of course a 450 cube engine is a different beast and takes to 'Granny shifting much better.
Where I am and with only 357 cubes, that kind of gearing (3.77) would make 5th pretty useless. This ain't the autobahn for sure. To each his own I suppose?
I like my 3,77 and I certainly don't think 5th is useless I have lowered the rpm at 100km/h (60 Mph) now it is 2100 and it is a comfortable rpm range for cruising at europe highway speed 130 km/h to 180 km/h. As I mentioned in a previous posting 4th is more suitable on country roads at 80 km/h and 5th is only really needed on the highway unless you are ok with cruising as low as 1500 rpm.
If by performance you mean drag race I have no experience and can not comment on that. I have never raced my Pantera and I do not intend to do it either.