Need some bump stick 101

87vette81big said:
GM Corporate 8.5 good for up to 500-550 Flywheel Ft/lbs torque.
Momentarily .
Not no higher . My experience building & using them.

With the rear diff cover off, in the center of posi unit there will be an S shaped clutch pack preload spring also.
Diff case cross shaft pin runs through spring cutout.
Some Pontiac Grand Prix 8.5 had no clips. Bearing end axle shafts lke a 9", Dana 60, 9.300 Pontiac.
Be ball bearing or tapered roller bearing axle shaft bearings.
Click to expand...



Knowing how much torque you are applying (this assumes you have perfect traction with only a 10% slippage at your slick) to the axel here is a chart of aftermarket axels listing their failure points (on average).



28 spline axel________1.200" dia. ________ 4,571 lbs.-ft. stock (GM test data)
28 spline axel stub ___1.250" dia. ________ 3,787 lbs.-ft. stock Corvette (Dana 44)
30 spline axel________1.250" dia. ________ 6,473 lbs.-ft. stock (GM test data)
31 spline axel________1.315" dia. ________ 7,000 lbs.-ft. (Ford 8.8" rear)
33 spline axel________1.370" dia. ________ 8,200 lbs.-ft. (GM 14 bolt truck)
35 spline axel________1.500" dia. _______ 9,600 lbs.-ft. (Dana 60)
40 spline axel________1.710" dia. _______ 12,000 lbs.-ft.

Here is a web site with a great graphic that shows why spline count is so important.
http://performanceunlimited.com/documen ... guide.html
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keep in mind a 500 ft lb of torque engine running thru a 3.73:1 rear gear is exerting over 1865 ft lbs of torque, impact loads easily triple that MINIMUM, if you insist on leaving a bit of slack in the drive train and having 3500rpm launches with slicks[/color]

the 10 bolt GM rear will hold up to abuse but the 12 bolt is larger and stronger, but Id point out that I,ve built several 496 and 468 big block performance engines that easily shredded 12 bolt G.M. rears, so if you do expect to race, a car,with slicks or race tires, a stronger 9" ford or even stronger still DANA 60 would not be a bad idea[/b]

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No Grumpy it won't take one of your Pump Gas 496 BBC Belching out 650 HP & 700-800 FT/ LB TORQUE.
You have to trust me. I know GM 8.5 Rears very well.
Factory Posi unit is the best bang for the buck for a GM 8.5.
$100 Used. Rebuild. Or I can do it.
I have used up to 4.56 gears with a GM 8.5. Ok. Will live.
Correct parts & Blueprinting key to them holding up.
Chevy 12-bolt will cost $2k average start to finish.
Or more.
Guys are tight on $$$ all over I know.
 
Dana 60 Guys can't find or afford either Grumpy.
Mopar Dana 60 any super rare today. Days of picking up cheap for $150 long gone.
$2K to start. Truck rear Ok. Still take $1500 to narrow & build right.
The 1963 Ford F100 Dana 60-2 4.10 Posi Rear Semi float axles is super hard to find.
Same width as you were asking. Still have it for you.
 
87vette81big said:
Dana 60 Guys can't find or afford either Grumpy.
Mopar Dana 60 any super rare today. Days of picking up cheap for $150 long gone.
$2K to start. Truck rear Ok. Still take $1500 to narrow & build right.
The 1963 Ford F100 Dana 60-2 4.10 Posi Rear Semi float axles is super hard to find.
Same width as you were asking. Still have it for you.
Click to expand...
please understand Id truly love, few things better than, to send you a thick envelope of cash and have you refurbish that dana 60 for me, I really do appreciate the offer and will grab it iF its still available when I get some spare cash, and the first chance i have to lay my old geezer hands on some cash it will be going for that, but currently my older suns family financial needs are pretty much screwing up cash flow, making that currently not feasible
 
grumpyvette said:
87vette81big said:
Dana 60 Guys can't find or afford either Grumpy.
Mopar Dana 60 any super rare today. Days of picking up cheap for $150 long gone.
$2K to start. Truck rear Ok. Still take $1500 to narrow & build right.
The 1963 Ford F100 Dana 60-2 4.10 Posi Rear Semi float axles is super hard to find.
Same width as you were asking. Still have it for you.
Click to expand...
please understand Id truly love, few things better than, to send you a thick envelope of cash and have you refurbish that dana 60 for me, I really do appreciate the offer and will grab it iF its still available when I get some spare cash, and the first chance i have to lay my old geezer hands on some cash it will be going for that, but currently my older suns family financial needs are pretty much screwing up cash flow, making that currently not feasible
Click to expand...
I keep my word my Friend.
Its yours.
No One Gets That Dana 60 but You Grumpy.
If they try & steal it.....They will get a bad Huting from me.

BR
 
i know this thread is about cam selection but we have gotten into the full fledged topic of keeping your chevelle going in a straight line when you want it to. in my experience A BODY cars like to twist and flex noticeably with anything more than ~500 ftlb/tq and alot of guys run an airbag in the right rear spring at like 12-15 psi so they can keep it in a sraight line hooking on the dragstrip and not make a wicked right turn into the wall.

i have found that lowering the car and resetting the rear geometry using a set of LCA relocation brackets like these

http://www.summitracing.com/parts/upi-4 ... l/chevelle

does most of that same task but also keeps the car level and planted in corners and driving spiritedly around town.

admittedly, ive never built a G machine or autocrossed an A body car but with the power you are looking for and for the sake of traction i would recommend some of these relocation brackets to make your life a little easier. i have used the bolt in versions and later went ahead and welded them in place. there is a weld in version from the same company for like 85-90 bucks if you want to forego the bolt in process.
 
UMI has allot of quality products and love there products I am sure some of there products will make it to my build. I also like there adjustable rear suspension parts. I also like there kit for the front to fit full coilovers.
 
OK cam is going to be ordered in a couple of weeks but feel I might have an issue now I have added a curve ball by going to a efi setup is the 30121101 lunati going to play well with that or should I seek a different grind?
 
as long as the intake manifold power band and flow potential is similar to what you had mentioned before there should be no difference. i assume youre going to use some sort of standalone programmable system
 
it is the lunati 30121101 solid cam discussed before I will be using the pantera efi it is the 882c cam sensor model ls2 coil packs and more than likely ford racing 39lb injectors on a weiand stealth ram intake. Philly can you recommend a good budget inline efi fuel pump?
 
philly said:
bosch model 044, there are many knock off floating around from china for 50-100 bucks but a genuine bosch 044 wont cost less than 190 anywhere unless youre paying in fellatio.

http://www.bosch.com.au/car_parts/en/do ... lpumps.pdf

dont be fooled by imitations like this

http://www.ebay.com/itm/Genuine-Bosch-0 ... 88&vxp=mtr
Click to expand...

just curious since your bringing this up, how do you tell the import knock-off versions from the true BOSCH pumps when BOTH are advertized as BOSCH pumps..? what do you look for to determine the cheap import clones
 
grumpyvette said:
philly said:
bosch model 044, there are many knock off floating around from china for 50-100 bucks but a genuine bosch 044 wont cost less than 190 anywhere unless youre paying in fellatio.

http://www.bosch.com.au/car_parts/en/do ... lpumps.pdf

dont be fooled by imitations like this

http://www.ebay.com/itm/Genuine-Bosch-0 ... 88&vxp=mtr
Click to expand...

just curious since your bringing this up, how do you tell the import knock-off versions from the true BOSCH pumps when BOTH are advertized as BOSCH pumps..? what do you look for to determine the cheap import clones
Click to expand...


i only buy from trusted sources.

i think the only way to really tell the difference is to cut one open and measure tolerances (which in the bosch pump will sometimes be in microns) maybe inside you will see certain parts of the motor labeled in chinese? or flow test it.
 
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