Nbs rear end swap questions

[Hoosierlong90]

I apreaciate the reply I've had my eyes open for years at the scrap yards around where I like (southern ontario) and I've never seen one . The gmt 800s are a dime a dozen out here . The swap was just something that popped into my head I can't really trust the obs 10 bolt with the swap engine swap I wanna do . 6L ls big cam should make about 500 to 550 crank hp

You would be surprised how much abuse a 10 bolt that's maintained would hold up to on the street unless your wheeling it off road, then get a 14BFF and reposition the old perches on the new axle, weld them up, connect brake lines, get the right u joint and your pretty well set. I have been told many times to avoid the 14BSF (9.5) and get the 14BFF (10.5) unless you only have Bob the builder tools and want the easy direct swap. A full float axle is much stronger than a semi float. There is a lot of information on these axle swaps.
Good luck to you!

 

[Canadian_bob]

You would be surprised how much abuse a 10 bolt that's maintained would hold up to on the street unless your wheeling it off road, then get a 14BFF and reposition the old perches on the new axle, weld them up, connect brake lines, get the right u joint and your pretty well set. I have been told many times to avoid the 14BSF (9.5) and get the 14BFF (10.5) unless you only have Bob the builder tools and want the easy direct swap. A full float axle is much stronger than a semi float. There is a lot of information on these axle swaps.
Good luck to you!

Thank you for the reply . I was debating on the 14 BFF because my goals for this truck are a street/strip truck and I know those 14 bolts are heavy as frig but realistically that's what ill go with . I figure I can never kill that thing lol

 

[Markmartin01]

I did a 99 disc brake rear in a 91. Have to cut and move perches and shock tabs but it's pretty easy. 99 rear is a half inch wider so negligible. But new perches and shock tabs bc they aren't worth trying to salvage. The ujoint was even the same between 91 Z71 and 99 Z71 so it was an easy swap. I also reused the original 91 brake lines and rebent them at the calipers. Do really need an adjustable prop valve though bc the rears will lock at panic stop without one.

 

[Hoosierlong90]

Thank you for the reply . I was debating on the 14 BFF because my goals for this truck are a street/strip truck and I know those 14 bolts are heavy as frig but realistically that's what ill go with . I figure I can never kill that thing lol

Another option would be a ford 9". Thats what all the street and track guys prefer. They are not too heavy and very strong with many carrier and spline options. I build them all the time at my work to support 1000+ hp and tq. Also you can always weld a back brace on whatever you decide to go with and that will make it much more stronger. Just be careful and take your time with short 1" welds letting it cool between each weld. If not it will warp and bow like no other. Also make sure when your positioning your perches, write down all the measurements from original axle and always measure from the housing flange and not the housing itself. You might as well 4-link it with a panhard bar OR add ladder bars. Many many options out there but as stated originally, the 14BSF will be the easiest direct swap if you can find one. I'm in the midwest and see them from time to time for around 200-400$. Let us know what you decide to go with.

 

[HotWheelsBurban]

I did a 99 disc brake rear in a 91. Have to cut and move perches and shock tabs but it's pretty easy. 99 rear is a half inch wider so negligible. But new perches and shock tabs bc they aren't worth trying to salvage. The ujoint was even the same between 91 Z71 and 99 Z71 so it was an easy swap. I also reused the original 91 brake lines and rebent them at the calipers. Do really need an adjustable prop valve though bc the rears will lock at panic stop without one.

Thanks, good to know! I felt like the 800 series trucks were a little wider, but never got the tape measure out to see how much. Parking 2 Burbs side by side in our old carport (the 99 and the 06) was very tight! Same with the 90 R2500 Burb and the other 99 Burb.

 

[Canadian_bob]

Thank you everybody for the relpys . Amazingly I was able to find a 14bsf rear with 6 lug axes only an about an hour and a half away from me for 200 bucks (and thats maple syurp dollars not bald eagle bucks) . Picking it up tommorow . Now I just need to convert my fronts from 5 to 6 lug and ill be all set . Thank you everybody for the input and knowledge given to a guy .

 

[stutaeng]

$200 Canadian Pesos!? Isn't that around $150 Redneck Pesos? Holy smokes that's a bargain! Congratulations! What year and ratio does it have? Hopefully a 3.73/G80.

BTW, my brother did the front spindles swapped on his truck this weekend, but kept his 90 calipers. He went to drop off some tools at my house he had borrowed and his brakes were smoking, and he said it felt something was hanging up. After we talked a bit, I suggested he also swap the calipers that came with the 6 lug spindles.

So he went home and swapped the calipers also and it worked just fine. Something about '88-'91 brakes being different than '92+. His 6 lug set up came from like a '97 truck. Maybe something to look out for.

Let us know how your swap goes.