Can cam support gear change?
Thank ya sir. So test in 4th, even though it's the OD gear? Or should I test in 3rd?
Yup, in 4th. It will give you the best 'simulated' feel of the power available in that range. Your 4.1 with a .8 OD is about like a 3.28 ratio - so the power available in 4th at 3k will be very close to the power of a 3.23 in 3rd after you swap.
I'd play around with a few WOT pulls in 4th from varying RPMs as a 'passing test' to see how the car feels at 2k, 2300, 2500, 2700, etc. If you find that certain ranges are a no-go, then gear accordingly.
If you can comfortably pull from 2k in 4th on a good hill then 3.23's should be no problem on flat ground at speed. If it lugs too hard for your liking, then you may need more gear than 3.23, but less than 4.10. Finding which rpm range it pulls from will help make that call.
Obviously the lower you go, the longer you'll be pulling 1st-3rd, but I bet the difference won't be too noticeable for 3.55s, and probably just starting to be notable with the 3.23's. The shift to 3rd will probably be where disappointment shows up if you go too low.