bygblok

iTrader: (3)

just how good is the factory off-road replacement dana 44? I came across one that has 31 spline axles, a spool, 3.92 gears etc, etc along with southside bars. It's a factory piece from GM that they don't offer anymore and as wondering what the thing is worth. My true street car only needs to run on a 7.50 index(mid 11's for you 1/4 milers) and I'm having trouble justifying $2200 for a 9". Thanks, Bill

AlkyIROC

A new third gen Dana 44 was worth about the same as a bolt in 12 bolt or 9". If it hasn't been abused then it should still be worth about the same. Any third gen Dana 44 for less than $1000 is usually a good deal. I've seen them as low as $500.

bygblok

iTrader: (3)

thanks Stephen. I just don't know that much about the 44. Hey, why not go to a 540 instead of a 509? The bore/stroke ratio is better and it's about a cheap to build. I've done quite a few of them and it's a really good piece.

AlkyIROC

Because that means having to buy a 4.25" stroker crank. I already have two 4340 steel 4" stroke cranks

TKOPerformance

A Dana 44 is not quite as strong as a 12-bolt or 9". The Dana uses an 8.5" ring gear, and had factory axel splines from 28-31. That being said it is still a stout rear, and should be fine for what you are doing. Basically the GM 8.5" 10-bolt is a GM Corporate version of the Dana 44. I have these axels front and rear in my Blazer, both built as tough as possible. I've never had a failure in a fullsize truck with 38.5" tires and a healthy 350 that get 4-wheeled and driven hard all the time. Here are the specs for those that are curious:

Rear Axel: GM Corporate 8.5" 10-bolt housing, Detroit Locker, 4.88:1 Yukon gears, 30-spline Warn full-floating axel conversion kit, TA studs and girdle cover. '89 Chevy 4x4 IFS front rotors (centers machined oversize to clear full floating hubs), Cadillac El-Dorado calipers, Warn caliper brackets.

Front Axel: GM Corporate 8.5" 10-bolt housing, ARB Air Locker, 4.88:1 Yukon Gears, custom made Superior 30-spline axels with 765 u-joints with full circle clip retention, '70 Dana 44 outer knuckles machined for crossover steering, TA cap studs, NAPA Lifetime Gold Series upper & lower balljoints, tie rod ends, drag link ends, and adjusting sleeves. Stock 1/2 ton disc brakes and calipers. WARN Gold (all metal) manual locking hubs.

A lot of people in the 4x4 world malign the 8.5" 10-bolt as a weak axel, and prefer to swap to Dana 60 front and a GM Corporate 14-bolt rear. I've got less tied up in my axels than I would if I'd stepped up to that hardware, and built them with equal parts. The difference is that the rears are about 100 lbs lighter in front and 200-350 lbs lighter in the rear (depending on the version of the 14-bolt). Less sprung weight means better acceleration, and a more nimble truck. I've also got at least another 3" of ground clearance with the same size tires. I can also move the axels around by hand if I ever had to take them back out, because they are light enough that I can physically pick them up. The point is that bigger isn't always better, especially if you don't need the extra beef.

bygblok

iTrader: (3)

thanks alot for the info. I've seen those axles in 4wd's all over the place but never in the rear of a car. This rearend was actually sold for the f-body's through GM performance and originally went for around $1500 from what I have seen. It was marketed as an off-road package for performance applications. That being said I'm trying to see what I can get it for. He also has southside bars and a crossmember too. Trying for a complete package deal. I just don't wanna break it as soon as I shove 500hp at it. Tha would really suck!!!!

AlkyIROC

I ran about 550 rear wheel hp through a beefed up 7.5" diff running low 11's with no problems. I only swapped to a 9" when I installed a transbrake.

TKOPerformance

The secret to making any rear live is careful parts selection. On any salisbury type rear like a 10-bolt or Dana the major weak link is the caps. Use studs and a girdle cover and most of your problems will go away. This will keep the gears running in the right alignment. When the gears are allowed to move when the housing flexes this is what causes them to fail. A buddy of mine does mud bogs. He has a Dana 44 front and a 9" rear in his truck (F150, 38.5" tires, 390 V8 built up a bit with a C6 and NP205). He's broken both rears running stock parts. The 9" broke the factory cross pin, he upgraded to a stronger cross pin and hasn't had a problem since. The Dana 44 blew a set of gears apart. It stipped the teeth right off the ring gear. Obviously the gears came out of alignment and the pinion was able to load the teeth too high, which caused the teeth to shear right off the gear. A set of studs in the caps and a billet cap on the weak side solved this problem (he couldn't run a girdle, which would be a better solution that the billet cap, because it would interfere with the tie rod). It wasn't much, but those simple parts were the difference between a season where he didn't place and a season where he placed 3rd overall and won some money.

Decent axelshafts are also a good idea. Moser has some nice and very reasonable 10-bolt shafts. Superior is another great manufacturer, though you can't buy directly from them. I have a custom set of 30-spline 4340 front shafts for my Blazer that are beautiful. You can buy them through Summit and other vendors.