A friend has a 741 case with sure grip 3:91 gears he wants to trade. He said at highway speed they are noisy. I haven't heard them as they are already out of his car. Should 3:91's have any noise at all or is this normal. He said he had them checked and they were set properly. I have 3:23's right now and they are very quiet. Do you think there should be any concern?
Thanks everyone, Russ:)

A good gearset is quiet. Worn gears can/will be noisey. Poorly setup or improperly broken in performance ratios may also be noisey. If it's noisey, it's not fatal. But I'd want to ride in the car, inspect the teeth and run a pattern on it before I took it in trade.

Youz guyz ... YOU want to hear NOISEY ? ... throw in a 5.57 pig

ONLY way yu can drown-that-out is to OPEN UP the headers

I have had 3.91s in 741 case set upn and all new bearings and there is still some noise that is ring and pinion related. I have a set 4.30s and 4.56s in 489 cases and they are quiet. I'm convinced once they have a pattern set you will never get rid of all the noise. I can say the noise is ther but they have survived so far 1 year and several dozen hard passes with M&H's.

Thanks Dave, Robert, Eric, and Paul. I appreciate your expertise and understand I need to be careful. I think I will ask to drop them in and take it for a spin before I agree to the swap...and listen closely, check the pattern:)
Points to ponder...thanks all,
Russ:)

I have a 741 case 3.91 and it is very quiet.

I've got a 489 4.56's on a spool that sound like the car has a GMC blower on it.