Rearend advice

[eventhorizon66]

I'm building an '85 C10 shortbed. The plans are a daily driver with RamJet 350 and 700r4. My problem is what rearend I should go with. I was originally thinking 30 spline moser c-clip axles and torsen diff for my 10 bolt. But I am not sure if that will be strong enough. I know the RamJet's no hot race motor, but the c-clip 10 bolt is pretty weak and I don't want a rear wheel passing me on the freeway. But I am looking at shelling out about $2K for a built 12 bolt or 9". Any suggestions? Also does anyone know if my stock rear is a 28 spline or a 30 spline version?

[lowc10]

stock would be a 28

[RSBAD454]

That 10 bolt is plenty strong for a little ram jet 350....like you stated, it's not a race motor. Plenty of built 10 bolts living beneath 8 second cars especially if you add 30 spline axles.

[midnite rider]

Why not just build a ford nine inch and never worry about it again. I dont recommemd wasting money on building the 10 bolt. I mean they can be built, but why when for a little more money you can have peace of mind knowing you have a strong enough rear end

[RSBAD454]

Why not just build a ford nine inch and never worry about it again. I dont recommemd wasting money on building the 10 bolt. I mean they can be built, but why when for a little more money you can have peace of mind knowing you have a strong enough rear end


Well, if he plans on adding more HP and Torque later, then Yes, add a 9 inch or Dana 60 to be prepared. If he plans on just keeping it as a driver with a little power, 10 bolt will be just fine.

[eventhorizon66]

Thanks for the advice guys. Does anyone actually own a 10 bolt equipped truck living behind a stout motor?

midnite rider: Believe me I would normally take your advice in a heartbeat, but in this case $1200 could break my budget. And I don't want to go overkill if its not necessary.

And no I do not have any plans of modification beyond the RAMJET at this time. When I finally make it my play thing and dump in a 427 LS-based engine it will get a new rear, but that is at least 5yrs off.

[RSBAD454]

Thanks for the advice guys. Does anyone actually own a 10 bolt equipped truck living behind a stout motor?

midnite rider: Believe me I would normally take your advice in a heartbeat, but in this case $1200 could break my budget. And I don't want to go overkill if its not necessary.

And no I do not have any plans of modification beyond the RAMJET at this time. When I finally make it my play thing and dump in a 427 LS-based engine it will get a new rear, but that is at least 5yrs off.

Well, I have a 433 inch BB in my 81.....10 bolt 28 spline with a Eaton carrier. My guess is that it's some where between 450-500 HP. I haven't had any problems on the street, but adding slicks would be a different story.

[44gmcnewf]

beef up the 10 bolt or see if u can get a 12 botl or 14 botl at a junk yard for cheap

[RSBAD454]

Anymore.....I wouldn't waste my time using junk. I'll spend the money for a crate rearend or build one with the top of the line parts.

[eventhorizon66]

Thanks for the peace of mind RSBAD454. A BBC beating on a 28 spline 10 bolt, I guess in that case traction (or lack there of) becomes a safeguard.

I have decided to upgrade my 10 bolt with either Strange or Moser 30 spline axles and go with either a Torsen or TruTrac limited slip carrier. Gearing...I dunno...maybe 3.73's.

Thanks for all the advice.

[N2TRUX]

How hard you planning on beating on this thing? It's only a 350 hp motor, not a 650 hp. The 10 bolt will hold up just fine behind the Ramjet and 700....;)

[RSBAD454]

How hard you planning on beating on this thing? It's only a 350 hp motor, not a 650 hp. The 10 bolt will hold up just fine behind the Ramjet and 700....;)

I concur.....I have a 8.5" 10 bolt in my truck. If I plan on throwing some serious HP to the ground, then I will spend 3K and buy this:

Complete Dynatrac 60 axle assembly with 12 month limited warranty
Heavy-duty Standard cut housing (max warranted pinion angle -
10 degrees)
35-spline, 1.5”, induction-hardened, alloy steel axle shafts
Vented rear disc brake assemblies with parking brake & 6 on
5.5 bolt circle
Braided stainless steel brake hose kit (Subtract $109 to remove)
Choice of ring and pinion ratio (3.54:1-7.17:1)
Trac-Lok Limited slip differential
Best pinion angle for 4-6” lifts
Billet steel housing ends
Large tapered roller axle bearings
Heavy-duty steel retainers
D60 heavy-duty steel differential cover
1350 yoke (Yoke Kit included.) (Other yokes available call for pricing)
Shock mounts, pair (Subtract $40 to remove)
Width 66” (Stock ranges from 64.5” to 66”)
Assembly is finely detailed with a hi-gloss black finish
http://www.dynatrac.com/images/image_products_72hdsraa.jpg

[N2TRUX]

That's a serious set up. If I ever break mine, I'll buy another one for 100.00 and go at it again. 10 bolts are a lot stronger than everyone gives them credit for.

[RSBAD454]

That's a serious set up. If I ever break mine, I'll buy another one for 100.00 and go at it again. 10 bolts are a lot stronger than everyone gives them credit for.


I concur....all the hype about them being weak is from hearsay anyway. Just because someone had a stock 28 spline 10 bolt behind a 800 horse motor with slicks and broke axles etc....they are all automatically junk. You do have to add some goodies to make them live behind high HP motors, but how many here are throwing serious HP/Torque at them? Most truck 10 bolts up till mid 90's had 8.5" ring gears and a bigger splined pinion shaft than a 12 bolt. 12 bolt ring gears are only a 1/8" bigger on each side than a 10 bolt. There are plenty of small tire 8 second cars out there running beefed up 10 bolts and living.
http://chevyhiperformance.com/techarticles/p113383_image_large.jpg
How strong is the 8.5-inch 10-bolt? Well, let’s put it this way: Both Dave Henninger and Kurt Urban run these 10-bolts (with spools) in their respective Camaros. Henninger has run as quick as 8.68/151 mph, while Urban’s Camaro runs 9.20s/145. Henninger has never broken a gear and has logged hundreds of runs. That should settle the question of durability.

[midnite rider]

Not really they are a fine daily driver rear end, but they are known as a weak link for a reason. i just dont understand why you want to spend alot of cash upgrading a weak unit instead of building a strong bulletproof rear end. just my 2 cents worth.Seems like a big waste of money and you still end up with a 10 bolt rear end.

[Old88]

Get rid of the G80 posi unit
A clutch type from a 70's camaro 10 bolt will live behind a RJ350

[chevydad]

the 10 bolt is fine. find yourself an old posi from an 60's or 70's car(mine cam from a camaro) and use it. i have basically the same motor as you, mine is carburated with a similar cam and i run at the track all the time using slicks. all is good.

[Old88]

The 60's 10 bolts had 8.2" ring gears
The 70's 10 bolts had 8.5" ring gears
They will not interchange.

[RSBAD454]

Not really they are a fine daily driver rear end, but they are known as a weak link for a reason. i just dont understand why you want to spend alot of cash upgrading a weak unit instead of building a strong bulletproof rear end. just my 2 cents worth.Seems like a big waste of money and you still end up with a 10 bolt rear end.

They are known as a weak link for the reason I typed above. It's how someone wants to perceive the 10 from someone else's failure. For a 600HP street driven vehicle with 30 spline aftermarket axles and bearing cap studs, they will hold up just fine. Like I also stated, if you plan to run more HP and add more traction, then yes.....you should upgrade to a more pricey setup.

[nic]

Many of the horror-stories about the 10-bolt come from the earlier versions... Imagine putting 400 hp into your spindly 1963 Nova chassis...

In all, there are at least four or five versions of the GM 10-bolt, ranging from the 7.5 ring-gear junk (often found under 60's non-performance cars (such as 6-cylinder Camaro's and Nova's) to the much-improved 8.5 ring gear late-models (first available in late 70's trucks, Camaro's and Nova's). The later versions can live very long lives under most performance applications (many lower level circle-track classes mandate GM rear-ends).

My personal experiences include the 8.5 ring-gear model under my 84 C10... It is set-up with Richmond gears, 28 spline axles and a Detroit Truetrac. It does at least a burn-out a week and has never given me any problems behind my 400+hp 383 and manual valve-body TH400 (pretty good for the original 180,000+ mile housing)...

If that isn't enough, look for a 12 bolt... They are plentiful and relativley strong. We recently swapped the BOP 12-bolt in my brother's Cutlass for a Chevelle 12-bolt posi (with new gears) for less than $600.

If you have to get a 9" Ford, look for Late 70's LTD's (often LTD II's), Ranchero's, Mercury Montego's and similar. Many of these have flange-to-flange widths similar to many GM chassis and can usually be bought for under $100. Of course they will have control arm brackets that must be removed to add leaf-spring perches... These rear-end's axles are often found with the same 4.75x5 bolt pattern common to GM midsize cars.

If it's a Dana 60 you want, look for 80's Dodge 2500 and larger pickups. Like the afore-mentioned Fords, they are pretty worthless sitting in the junkyard and will usually bring little coin... Many even have factory lockers, but will usually come with funky bolt patterns (new axles...) Just watch out for the Dana 70's and 80's found under some duallies.

I'd build the 10 bolt with a decent street-differential and let it go, when (if) you break it, there are millions more in salvage yards waiting to have your differential swapped into them... Keep in mind that if you already have a drivable setup, you'll have to get another driveshaft if you change to anything other than another 10-bolt...

[RSBAD454]

Couldn't have put it better myself.:matty:

[chevydad]

The 60's 10 bolts had 8.2" ring gears
The 70's 10 bolts had 8.5" ring gears
They will not interchange. i don't know the exact year of the camaro it cam out of, but i think it was early to mid 70's..