man the car takes off just as good ....and when my blower gets on...(after an engine rebuild by the look of things...see other post) the ratios will meen nothin....but the cruise ratio is unreal ...lower revs meen lower fuel consumption for me on the highway on the way to work..works great
thanks again all those who offered their great answers...highway = a breeze

Mate screw changing the diff ratio !
Keep your 4.1:1 ratio and stick in a 5 speed,
the extra money spent will be well worth while, not only for highway cruising, but you get to keep your faster acceleration with the standard ratio and good fuel economy !


And YES this is open to healthy debate

That's a by-product of changing diff ratios or changing wheel & tyre sizes. You will be now traveling faster than the speedo shows, so be extra carefull in school zones etc.
You have a ute gearbox, so it's possible that the speedo's worm drive on the gearbox output shaft may be diferent. If i remember. i will check my parts book when i get home. If this part is the same as the sedan, then using a passenger car output drive from a sedan /coupe will help to correct it a bit.

i found a 3.7 :1 straight away and chucked it in and works great only prob is that it seems to have put the speedo out which sucks

Grab a stanza center, they use a 3.9 ratio, same as the coupe's ratio only in the H165 family.

Thats the center I use in my coupe

Cheers
Damo

Your question was comprehensively answered in your other thread "Bluebird diff - straight swap"
That response,... & this one, refer to the diferential, & not the rear axle assembly.

Yes, i got your PM.

At the risk of sounding repetitive, you will find that Nissan /Datsun model 910 Bluebirds in the series 1 & 2 [up to January 1985 build] almost all used the H165 diferential in 3.9 to 1 ratio. There were two exceptions.
The four speed manual sedans used the H165 in 3.7 to 1 ratio & the four speed wagons used the larger H190 diferential.

Your ute used the H165 diferential in 4.11 to 1 ratio. To fix the gearing, fit either of these suggested diferentials. The 3.7 one will be hard to find, but will give the best cruising ratio, however, the much more common 3.9 ratio is a good choice too.

Now thats twice in three days i have writen this up for you, lets hope that you are able to benefit from this info.
If the revs are still too high, then use a larger diameter wheel & tyre combination on the rear. If the revs are still driving you crazy, then leave a little earlier & drive a little slower, & thats the lowest cost solution of all.

Series 1 and 2 Bluebirds should fit the bill. H165 diff. . . There should be a couple of ratios available. 200B's may also fit. IT may pay to pull your centre and take it with you to compare. Check axle spline count.

Please help

hey i just gotta new job where i have to travel 45 kms to and from work and most of it is in 100kmph zones and my 1980 ute is reving off its tits at 100kmph well a good 3500rpm to 4000rpm = annoying anyways i was told striaght up that i can get a bluebird diff ...(centre i think) and bolt it in place of my standard diff centre and it will change the ratios enough so that i can cruise at 100kmph at an easier rpm level
.....if so does anyone know what exact model etc it would be because i need it so bad i wont be able to stand anymore of this rpm

doesnt have to be bluebird just needs to be easy to get and easy for me to fit

thanks sooooooooooo much for any help i realy appreciate it