C-1 rear differential for drag racing
 

What is the best way to strengthen a C1 rear end for drag racing? OK, I KNOW the BEST way is to replace it with a 9 inch Ford (did I say that??) or a Dana 60. But is there anything that that can be done to the stock rear end to strengthen it? Different spider gears? Stronger axles? Aftermarket gears?

Looking for replies from the guys who have "been there and done that".

Thanks,
Rex

Currie Enterprises can build you a ford 9" with whatever brake setup or bolt pattern you'd like. The finished rear end is literally a bullet-proof bolt-in. Don't have one, but saw one go in. Don't look for the item on line, but call them for details. Definitely one good way to go.
Reed

You don't say what kind of engine you have, but the 8.2 Chevy can be strengthened quite a bit to handle more power. Yes, stronger gears, aftermarket axles and changing the spider and axle gears to the 30 spline 8 3/4 mopar internals will strengthen it a lot. The axles can be changed to Dutchman, or other after market, but they are still pretty small without going to a special oversize bearing, that requires machining the housing. Aubrey Bruneau has a billet cap that fits over the power side of the rear cap, that will help keep the carrier from being spit out the back end of the housing. Nobody that I know of makes a spool, so for me anyway, the best carrier is the 60-62 carrier. You can identify it by the left handed bolts that hold it together. It also has more clutches. After all that, you MUST not have any wheel hop, or you'll break the spiders. Running a 'soft' clutch, keeping the slicks to about 7 or 8 inches where it won't twist the pinion in two at clutch release, high numerical gears, and don't do 7,000 rpm launches, and it should do reasonably well, unless you are putting a lot of power through it. Auburn makes a Pro series center carrier that is probably stronger than the stock unit, but no one makes a heavy duty yoke, and the 1310 series u joint is all you can run. Using a solid joint will offer more strength.

Another option, that kinda sorta looks like the Chevy rear end is the 57-64 Pontiac rear end. It has massive axles, a bigger, stronger 9310 ring and pinion, will take big power, and I believe there is someone who makes a spool for it, a billet yoke, and billet caps for the case. They are really pricey, though.

PS- using a line loc to preload the gear so you don't 'shock' it will also help

We used to sell the Posi case with new machined caps. The spider gears and R&P were heat treated. The held up reasonably well, but remember back the (60s) most classes were limited to 7" slicks. We went to using Olds/Pontiac rears, but with a 6:17 ratio we still didn't get that many runs before they were torn up.

By the time you waste sourcing all the parts and the expensive it is easier, and in the end far better going to a 9" Ford rear. I had one made for my '62 a few years ago. Retained the drum brakes. Only very slight body modification was taking some of the radius off the spare tire well. I got enough off the clear and not go all the way through the well.

What are you up to, Rex?

Expiring minds want to know....

Hi Jim,

Just "thinking" about something.........................for now. And that usually gets me in trouble.:D

Happy New Year !!!

Rex

And if you don't quit now, Rex, it's going to end up costing you $$$$$. Mark my words!

Happy New Year to you, too.

Jim

Jim, that's EXCELLENT advice......................as always from you. I just hope I can heed your advice this time.:D LOL

Rex

Ha ha ha! You said it best Rex!

And....I've seen Jim's garage, so he's speaking from experience!

Happy New Year to you and your Mrs. Rex!

Pat

Yeah.......................between you and Jim, I'm embarrassed by my old junk.:D:D

And here I am thinking about bringing something else into the stable. I must be :crazy2:.


Happy New Year to you and yours too Pat.:thumbs::cheers:

Rex

Well, Rex, I can help. Send me that trashy dual air meter FI unit and I'll haul it off to the landfill for you. I won't charge you anything for the service and afterward you can once again hold your head high.

Really good info here guys. Thanks! I haven't messed with a Chevy drop out chunk in years. Good to see there are still parts around to improve them!

JIM

When enough time goes by people forget what was learned from past mistakes.

The original differential simply will not hold up to repeated dragstrip abuse no matter what modifications you make. This assumes you are running over 300hp.

These rearends were considered junk then and now for any serious HP.

Tom, in your opinion, is the Eaton carrier stronger than the Dana type?

I remember back in the day, Jenkins was running 28 spline axles in his 63 Super Stocker (out of Chevy truck series I guess), and he drilled the rear housing and welded a reinforcement on the outside with a nut that was centered over each bearing cap. He had a bolt running through the nut and preloaded the bearing cap to help keep it from blowing the cap off the back of the case.

Thanks Jim for your most generous offer. However, I don't want to offend Al Gore and Jerry Brown by contributing to "landfill waste" so I'll just send it to the aluminum recycler here in town. I think aluminum is up to $.026 per lb so I'll get about $14.76 for it. At least it will go to a good cause.............................new Coors and Budweiser cans.:D:cheers:

Rex

I feel a NEW Eaton is stronger than an ORIGINAL (50+yr old) Dana posi unit. But the new Nitro unit without question is better than the old original Dana posi unit.
Thus, today, a new Eaton and a new Nitro are probably a toss up. I like both and have installed both.
And the price is about the same for either one.

Back brace and chromoly axle tubes.

jp

I'm looking at an ex NHRA Super Stocker. It has a Dana 60 in it now. I was just thinking the 9 inch Ford would look more like the stock rear end. But a Dana 60 would be strong for sure.

Thanks everyone for your comments. Take care and STAY WARM !!!!!

Rex

cheap way out
 

back in 62/3 I ran 4.56 with welded spider gears, tough on tires but a bear off the line. Never broke an axle but if you did all you needed was a long pipe .
Tom:eek::eek: