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'38 chev rear axle replacement

4K views 19 replies 6 participants last post by  Too Many Projects 
#1 ·
I just bought a '38 Chev in original condition and will be replacing the drive train. I've seen different rear axles in these cars and am wondering which fits the frame the best. I am leaning towards a 8.5 10 bolt GM over a Ford. I see many from an X or F body car but need to know about the S10 series fit too. Any advise from the seasoned builders/owners will be appreciated....:)
 
#3 ·
It's going to depend on how wide you want it. The X body rear ends are 60 inches wide and the 2nd gen F body rear ends are 61 inches wide. If you don't need strength you could use a G body 7.5 rear end that is 58 inches wide. The S10 8.5 rear ends have tapered axle tubes, so be aware of that.

That chart has been around for a long time and is in serious need of some corrections. The '67 to '69 Camaro, '64 to '67 Chevelle and '68 to '79 Nova rear ends are all exactly the same width at 60 inches. The chart has them all different. Also the '68 to '72 Chevelle and '70 to '81 Camaro rear ends are 61 inches wide, not 62 1/2 like the chart says.
 
#4 ·
I haven't found a chart for the width of the stock axle to know what I need. I see chassis engineering has conversion plates to moves springs out for wider perches. I'd like to keep the axle as narrow as possible to have more wheel offset to the outside (dish).

I thought the chart for Chevelle's was wrong, as I have a '66 and a '70. They both have '70 axles in them and I have to be careful with dished wheels on the '66 because of the increased width.
 
#9 ·
Great looking car! When I bought mine in 2003 for 4500.00 it was a running driving southern Idaho car. Thought I would just clean it up and drive it as an original car. First time in it I changed my mind. It felt like a truck! I now drive mine every day that the sun is out. So much more fun than original. Keep us up to date with photos as you build and hopefully it wont be a 7 year project like mine was.
 
#10 ·
You have a great car. I don't plan to spend 7 years converting mine but then I'm sure you didn't either. Things always come up and take time and money. I like the bumpers and running boards on these cars. Many I see don't have them. We are the home of MSRA here and have the Back To the 50's every year. They set a record attendance this year with around 15,000 cars 1964 and older on the state fairgrounds. Quite the spectacle to see...:cool:

I hear ya about riding like a truck.....I brought this back From Pagosa Springs CO last December. 1952 2 ton. This is like having NO suspension and with 6.13 rear gear it's goes a whopping 48 mph...:D



This was my daily driver for the last 17 years. 42 years of driving some type of commercial truck. I just parked this for good 2 weeks ago. Know anyone looking for a '92 Pete ...;)

 
#11 ·
Looking at that car, almost a shame to change it, but why not! Just makes it better.

A 9" may be overkill, the 8" is a good compromise - that is if you can find one. I 'ended up' 7-8 years ago with a 9" simply because I just could not find an 8" that wasn't so rust pitted that it was well weakened. Also, the 9" has probably many more choices of replacement gear sets.

With that blather said above, another choice is the Ford 8.8 rear ends. Very available in salvage yards. Are 56.5(Ranger p/u & early Explorer) to over 61" (Crown Vic, etc) wide, depending on the source vehicle. Many have disk brakes, gear ratios go from the high twos to the low fours. Every part is still available at your local parts store (drum brake parts for an 8/9 incher are virtually impossible to find at 'local' stores)

Dave W
 
#12 ·
Dave, I was thinking the same thing about the originality of it. I have been looking for a turn key rod or at least a project well along but didn't find anything that met my goals. I did find a couple that were close but I couldn't afford the 27-30k price tag...:rolleyes:

I will most likely keep all the original drive train parts on the shelf. Many of the mods necessary to rod it can be had as bolt on.

I have ample room to store stuff but I need to purge a lot of what's here now to make room. I will be working on a '67 GTO basket case over the winter to sell as a roller next spring. I also have a '69 GMC K10 that will get sold and all the extra parts I have to convert it to a Chev. Those 2 vehicles and all related parts take up the area of a 3 car garage.

I'm leaving here in about 45 minutes to go look at and, hopefully, bring the '38 home from TN. If it's not what the owner described or the pics show, I will drag an empty trailer back with me.
 
#19 ·
The Malibu 7.5 is 58 inches wide. That's 2 inches narrower than a Nova rear end. The 7.5 is not very strong, but you can help it by installing a 28 spline Eaton Posi, 28 spline Moser axles, T/A Performance cover and correctly setting up the gears. If your 7.5 is mounted by the axle tubes then you need to strengthen them too. The 7.5 has 2 5/8 inch tubes, which are not as strong as the other GM rear end's 3 inch tubes. You can fully weld the tubes with nickel to help hold them in place in the center casting. The plug welds tend to break when the rear end is mounted by the tubes. Nickel is the only material that you can use to join steel and cast iron. Welding them with steel will look fine, but it will break away from the cast iron if it's stressed.
 
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