I was running Bravo 1 1.36's in my 370 Baja. I upgraded power years ago and am running 600+ HP. I have recently upgraded to XR's with 1.35's gears. I have benn told that I would loose speed going to XR's of course Mercury Racing says never. Can anyone put the debate to rest for me. I seem to have people on both sides.
Thanks in advance.

I could not see where u would lose speed !????

Larger gears, more friction= slower

HAHA,,,,what .02 MPH ???? thats bs.

I bet you do not even notice that !

That's what I've been told... but then again you sound like you know it all- just not the answer!

I lost 2 mph switching to an XR.(gps) I was told it was because of the straight cut gears in the drive.

I am wondering if that loss is after the new drive was broken in?
My point is, take an nicely loosened up B1 that has a stack of hours on it.. then switch to a new tight XR and see a speed loss. After 50hrs or so on the new XR does the speed come back, or is it in the middle of summer heat and the power is down? Does the new drive have the same water pickup/nose cone?

I can see the theory of more drag on the gears, especially the XR's that grind metal off to them to break in. I just wonder if anyone has looked at it very carefully and when they made the switch, made sure the only thing that changed was the upper gears???

Just thinking out loud here. I know the general conscense is that there is a loss. I have not had the opportunity to test it out.
Dick

I have a 353 Fastech and went from Bravo 1's to XR's a year ago. I went from 81.9 MPH GPS to 78 MPH GPS. This has not changed in cool weather of hot.

I went from a stock Bravo 1 and replaced the upper with an Imco Extreme Advantage SC. I lost about 100-150rpm and 1-2mph on the top end. This was in my Pantera 28.

The stock upper blew apart at 210 hrs. The Imco was still going strong with 280hrs on it when I sold it.