madfabcustoms Posted February 4, 2010 Report Share Posted February 4, 2010 hey guys we just picked up a ole 521 and plan on puttin a 4.3L v6 in it and was wondering if is there any way to beef up the stock diff or any stronger ones that would be a good recommended upgrade .. thanks for any input ..lovin this site Quote Link to comment
datzenmike Posted February 4, 2010 Report Share Posted February 4, 2010 The stock H-190 is good for 280 ft lbs of torque. It's the torque that kill the rear ends. Quote Link to comment
Hyphy Posted February 4, 2010 Report Share Posted February 4, 2010 depending on the year on that 4.3, you are probly rather close to its limits. One of the bigger concerns with the replacing the axle for me was the overall width. You could either do some of your own research on axle lengths or get one and cut it down. I opted to do an IRS subframe from a 240sx. Theres also a build thread from a member named Fineline. He found a place to get a beefier rear end for his 620 which would work for you aswell. Check out that build for the link. edit. wasnt Fineline but this is the link i was referring to http://www.reiderracing.com/ Quote Link to comment
madfabcustoms Posted February 4, 2010 Author Report Share Posted February 4, 2010 cool cool yeah its a newer 4.3 1998 ..just a doner motor from our s-10 .. its gonna be funnn ha Quote Link to comment
Suspect Posted March 2, 2010 Report Share Posted March 2, 2010 I broke a rear end before, entertaining to watch the drive shaft fly from under the truck. The rear u joint broke and the tail of the transmission broke. This was in my S-10 with a 350. Quote Link to comment
Farmer Joe Posted March 3, 2010 Report Share Posted March 3, 2010 what are you planning on doing with the truck? is it gonna be a 1/4 mile truck or just a driver? are you gonna have bug wide tires or relatively stock sized tires? if its a 71 then its prolly gonna have either 4.88s or 4.37s, so depending on the transmission you might have to change the gearing. now if your gonna just make this a driver, then i would just stick with the stocker and if necessary just swap out the center chunk got a different gear ratio. ive built many chevy luvs with hot smallblocks and never had stock rearend pop. they all just end up breakin the tires loose. popped one with a 4 cylinder, but that neither here nor there lol. now if youve got a manual trans and your gonna be bangin gears and such, then you might keep the rearend out of the s10 and possibly just have it narrowed a few inches. i had a 74 620 that i put a 4.1L buick v6 in, and i swapped an early s10 rearend into it. the leaf perches are only a 1/4in wider on each side on the s10 rear than the stock axle. so this should be the same for the 521. reason why i say youll have to narrow it is cuz the 521s axle from drum to drum is a little narrower than a 620 rearend. my 620 that had the s10 rear had the outside of the tires basically flush with the bedside. Quote Link to comment
Guest kamakazi620 Posted March 3, 2010 Report Share Posted March 3, 2010 What about the chevy LUV rear axle??? should be close to same width and six lug :D Quote Link to comment
Farmer Joe Posted March 3, 2010 Report Share Posted March 3, 2010 What about the chevy LUV rear axle??? should be close to same width and six lug :D IIRC the isuzu axle is very close to the same ring gear size as the datsun. they do have the spring perches in the same spots as an s10 axle though. so putting an isuzu rearend is an option, but id just stick with the datsun rearend if were gonna mess around with import axles. Quote Link to comment
Guest kamakazi620 Posted March 3, 2010 Report Share Posted March 3, 2010 aahhh ok gotcha!! forgot the LUV was a isuzu,what about a Astro van rear??? some of them were 6 lug but i think their way wider??? Quote Link to comment
Farmer Joe Posted March 3, 2010 Report Share Posted March 3, 2010 aahhh ok gotcha!! forgot the LUV was a isuzu,what about a Astro van rear??? some of them were 6 lug but i think their way wider??? all the astro vans had 5 lug axles. the bigger 1500 style vans were the ones with six lug axles. and the astro vans had a wierd clampling style mounting setup for the leaf perches. 1 Quote Link to comment
Guest kamakazi620 Posted March 3, 2010 Report Share Posted March 3, 2010 all the astro vans had 5 lug axles. the bigger 1500 style vans were the ones with six lug axles. and the astro vans had a wierd clampling style mounting setup for the leaf perches. no they Didn't!!!! Quote Link to comment
Guest kamakazi620 Posted March 3, 2010 Report Share Posted March 3, 2010 I kno ma Chevys yo!!late 96?? 97 they switched ta 6 lug Quote Link to comment
Farmer Joe Posted March 4, 2010 Report Share Posted March 4, 2010 mkay, how wide is it? 521s are pretty small compared to an astro... Quote Link to comment
Guest kamakazi620 Posted March 4, 2010 Report Share Posted March 4, 2010 mkay, how wide is it? 521s are pretty small compared to an astro... ASTRO WIDE!!!!! dunno looks wider tho!!I'll measure one next time i;m at the yard,I betcha there the same as S10 Quote Link to comment
denveratsun Posted March 5, 2010 Report Share Posted March 5, 2010 It might help this conversation to assume that the strength of the Datsun rear will be plenty sufficient and that it really comes down to a gearing issue...so... Which rear ends had third-members swappable with his 1971 pl521 rear axle? Axle splines and diameter cross references anyone? :blink: And what gear ratio would be available? If stock is mid to high 4,s than what are some options? How low can he find (numbers low...not gearing low) in junk yards or donor axles? What were some factory options? Where are gear ratios indicated on the 521? Quote Link to comment
AtomChurch Posted March 6, 2010 Report Share Posted March 6, 2010 Toyota axles!!! haha Quote Link to comment
Guest kamakazi620 Posted March 6, 2010 Report Share Posted March 6, 2010 It might help this conversation to assume that the strength of the Datsun rear will be plenty sufficient and that it really comes down to a gearing issue...so... Which rear ends had third-members swappable with his 1971 pl521 rear axle? Axle splines and diameter cross references anyone? :blink: And what gear ratio would be available? If stock is mid to high 4,s than what are some options? How low can he find (numbers low...not gearing low) in junk yards or donor axles? What were some factory options? Where are gear ratios indicated on the 521? And POSI!!!!!!!!!! swaparoo!!!!!! Quote Link to comment
datzenmike Posted March 6, 2010 Report Share Posted March 6, 2010 It might help this conversation to assume that the strength of the Datsun rear will be plenty sufficient and that it really comes down to a gearing issue...so... Which rear ends had third-members swappable with his 1971 pl521 rear axle? Axle splines and diameter cross references anyone? :blink: And what gear ratio would be available? If stock is mid to high 4,s than what are some options? How low can he find (numbers low...not gearing low) in junk yards or donor axles? What were some factory options? Where are gear ratios indicated on the 521? H-190 All '72-'79 620 4.11, 4.375, 4.625 will fit. All '80- '86.5 720 2wd 3.364, 3.70, 3.889, 4.11, 4.375 will fit. The '82 200sx manual tranny has a 3.545 that will fit. Quote Link to comment
albyneau Posted April 23, 2011 Report Share Posted April 23, 2011 all the astro vans had 5 lug axles. the bigger 1500 style vans were the ones with six lug axles. and the astro vans had a wierd clampling style mounting setup for the leaf perches. Had an '89 Chevy 3/4 ton van once upon a time 5-lug, 8.5" 10-bolt rear.... My factory parts source said it's no fluke. Still got a brand new posi for one laying here on the bench, keepin that little spot dust free~ right over there! :blink: Wanna buy it...?;) 1 Quote Link to comment
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