high n mighty wrote:So you wouldn't want the extra width then??? And you know what a F100 diff will stand up to??
Anyone with serious answer please contribute, I know GU diffs are strong but geez, Effies have to be better or atleast equal.
All I need of I'm getting no well informed answers is the ratios and if the steering setup is completely different etc.
There is always a first

OK, I will try and give you an unbiased opinion. I have an F150 (same as F100), the rear 9" is a 31spline version, and is probably similar strength to the GU diff, if not a little stronger, due to what I think is better materials. Other's may have different opinions. weaknesses are in the LSD hat, and axle bearing retainer plates. both items are available for about $100 in stronger steel versions. obviously gears and lockers, stronger axles etc are all too easy and extremely cheap to get. the most you will pay for ratios is $300, 31, 33 or 35 spline alloy axles are $900 including thicker retainer plates, and 11/16 wheel studs, some with a lifetime guarantee.
in saying this, i have pulled out my 9", and am selling it, as i have installed a Corporate GM 14 bolt full floater diff. Much heavier, bulkier, and stronger. and quite cheap.
The front diff is a dana 44, quite strong, good for about 33 - 35" tyres, still quite cheap for ratios and lockers, can buy stronger axles straight from the states. I doubt they will be as strong as the nissan unit. I have kept mine, but am looking at getting a dana 60 in the future, probably what you should be looking at.
all said and done, i wouldn't change what you have, you already have the strength, maybe get a h260 (big nissan GU diff in some coil cab utes) and maybe some stronger birfields.
I dont think my 9" is much longer than a GU diff. maybe get some spacers or something. if you want my 9", it is 3.5 ratio, 31 sp, and i want $700 for it, can post anywhere.