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Rear end strength 63 Nova

10K views 15 replies 6 participants last post by  Kenny Brant 
#1 ·
I am new here and have a question on my 1963 Chevy Nova four door 194 six 3 speed on the column.

I am going to put a warmed over 250 six out of a 67 Chevy Nova in it and was wondering if a posi rear end would hold up. I have a shop that could build me a 3.73 posi using my carrier. I know the carrier isn't as strong as a full size Chevy 55-64, but would it survive a mild build up six?

Thanks, Kenny
 
#2 ·
Your pumpkin was designed to handle a 190 horsepower motor but it should be able to handle up to 275-300 horsepower. The weakest link in your rear end is the spider gears attached to your axels. It was because of this rear end breaking at the hit of the clutch with a 348 or 409 that the factory turned to Dana-Spicer to buy a modified Dana 30 and Dana 44 rear end called a 10 bolt (Dana 30) and a 12 bolt (Dana 44) rear end. Your rear end was designed to handle a stove bolt 235 cubic inch six cylinder and a new V-8 motor that was still on the drawing board that displaced 265 cubic inches (later all the way up to 283, and two years before it was replaced with a new larger bore hot small block the 327.

I have replaced a boat load of spider gears in those rear ends (and a few axels which is the next weakest part). You can fix the spider gear problem by machining a set of MOPAR spider gears by thinning them down to fit in the case. It takes a special case (with a "P" cast on the side of it) to use a factory PosiTraction; though there are aftermarket solutions that utilize a standard case instead of the very rare factory posi case.

Big Dave
 
#3 ·
Kenny it will be fine and ask them again about the carrier. To switch to a positraction the carrier will need to be replaced.
In my old 62 impala it took 300 horse power and a manual transmission shifted 6000 rpm's to break the rear end and that was because a ring gear spacer was used. Once built properly it never broke again.
 
#4 ·
Thanks for the information. I was hesitant to use the carrier housing in the Chevy Nova as it isn't as robust as the full size cars are. I will have a rear end built using the full size car carrier, I'm sure it won't be a "P" housing though.

This is just a toy for around town on the weekend. And I don't plan on standing on it very often I just want it to take it if I do.

I plan on a 3.73 ratio with a 5 speed OD transmission powered by a warmed over 250 six, what 225 to 250 horse and same torque.

The next problem is the transmission, I will look for a 5 speed out of a Camaro 305 or V6 and change the tail housing to a S-10 because I want to keep the bench seat. Right now will be a 3 on the tree. I know that 5 speed transmission is weak also.

I want this car to look as stock as can be, even the 4 lug wheels, although I put Ansen 5 slots 15's on it already.

Kenny
 
#5 ·
I think you have a good plan Kenny the 250 cid in-line six and Borg-Warner T-5 transmission copled with a stock rear end with 3.73:1 rear in such a light car will be both fun to drive, give great mileage compared to many high horse V-8's and still be reliable. All of ther components where designed to survive with that level of power (your getting close to the upper limit but you are still within the built in safety margin).

Big Dave
 
#7 ·
Has anyone used a locking differential? I have one in my 65 using a stock carrier. It replaces all the gears inside the carrier. It makes a quick clunk noise when it dis-engages a wheel for turns, but once I got used to that, I've grown to love it. It's 100% locked at all times when going anywhere close to straight.
 
#8 ·
Yup you can get a locker for 12 bolts and the Dana 60's now as well as that aftermarket nine bolt. They are great untill you try and drive through a curve with poor road traction and the rear end pushes you in a straight line because there isn't enough of a side load to disengage the rear end. But no worries, we rarely drive in ice and snow or wet oil soaked roads with our cars as they are generally fair weather cars.


Big Dave
 
#10 ·
I run my Eaton PosiTrac with 800 pound springs instead of the stock 200 pounders with 18 steel clutches (four extra clutch plates made of steel instead of with an organic clutch face) inside my rear to maximize the Posi part (the 22 plutch plate package doesnt hold up as well and eats into the splines of the case). It will differentiate grudgingly on dry pavement but in Florida between June and October it rains every day. Problem is it rains very little the rest of the year. So oil soaks into the pavement to leave a nice slick of oil on top of the road surface for unwary drivers in June and July (it has all washed off the road and into the ditches by August).

I have straightened out a few curves getting off onto the grass before getting the car stopped a few times (thank God we are a table flat state so there are no guard rails to hit, and DOT mows back sixty feet from the road edge to discourage road kill so all of the pine tree saplings are just out of reach). Of course running a twelve inch wide tire in the wet doesn't help matters either, but I was already crawling along under forty mph to keep from hydroplaning when I have gone off road.

I wouldn't want to hit a patch of black ice in the mountains of North Carolina, or discover sand on the road from a slide in the Rockies, or water and green moss which covers everything in the Cascades in Oregon and Washington state on a rainy day with a locker and a guard rail or opposing traffic a few feet away.

Big Dave
 
#12 ·
I rebuild the entire brake system including new hoses, replaced the wheel cylinders and master cylinder, had the drums turned down and the braking system is working fine now. It stops straight as an arrow when I let off of the steering wheel. I also put a 4.10 posi from a full size Chevy in it. sand blasted the rear end housing and backing plates, replaced the bushings, shocks and wheel bearings. u-joints and front wheel bearings. I was going to rebuild the front end but it works too good to need anything. It has no play in the steering and when going down the road you can let go of the wheel and it goes straight down the road, so I think as of right now I am going to leave it as is.

















 
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