CHEAPest way to convert rear axle bolt pattern to big bolt pattern???

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Ridge911

Ridge911

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Hello all,

I have a 1964 Valiant, slant 6 motor with an A-904 trans (I think). Its an automatic, its slow, and I'm keeping it that way. I assume it has the stock rear-end.

I'm upgrading my brakes in the front to discs from the 73-76 a-body. That involves the ~11 inch rotors with slider type calipers. This also involves having the front bolt patterns become converted from the small bolt pattern (5x4) to the large bolt pattern (5x4.5)

The fronts are not what concerns me. It is the rears...

What is the cheapest safe way to convert the rear axle to the large bolt pattern. This is a cruiser, no crazy V8 torque, I'm staying with the slant 6, and I have no interest in swapping in a huge new axle, unless that is my only choice. My '64 has a narrower rear axle than the newer a-bodies, so most newer mopar rearends will not swap right over. These are my options as I understand them:

1) I could get custom axle shafts, that are the proper length with the larger bolt pattern, and use drum brakes from something newer.

2) swap over a newer entire rear end and have it cut down, and the perches relocated, etc (ugh)

3) use an "adaptor" to convert the lugs from 5x4 to 5x4.5. Do I still have to get new rear drums? Is this safe for my mild use?

4) have a machine shop modify my current axle shafts to remove and install new lugs at the desired spacing, redrilling the drums at the same time. Is this safe for my mild use?

-Reminder: Ease and safety are my primary concerns. This is no drag car, it is just a fun crusier. BUT, I don't want to have to worry about the wheels flying off on the interstate.

I've read so much and most seem to recommend an axle shaft swap or a modified rear end. Many posts go nowhere or don't have much follow up so I'm always left wanting a little more. Most questions aren't about such an early model either.

Thanks for your patience, and tell me what I can add to make your assistance easier.
 
/6?...I'd go with #4. Get the machine shop to plug the old holes as well. This mod is not for higher HP cars, but for a 6, I think you;ll be OK.

Just my opinion.......
 
Ridge911 said:
Cool. Nice response time by the way! What kind of shop would do this kind of work? Driveline specialty shops?
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You're welcome. I would think any decent machine shop or fabrication shop should be able to help you out....local racecar-building shop?
 
66340SEDAN said:
I need some raid....there is a bug on my screen!!
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LOL... Me too!

Ridge911 I'd do #4 too. In your low hp setup it'll be fine. Heck I've seen guys put some serious power (400+ hp) to re-drilled axles but I wouldn't chance it in a high HP setup. Most any machine shop can re-drill them and weld up the old holes.
 
My buddy's running redrilled w/ about 350hp at rear wheels, no prob in three years at the strip. I'm planning the same with less hp, gotta be better than the adapt. I've got , I'm pretty sure one even still has left hand studs in it!!!
 
i ran a 340 4 speed barracuda with re-drilled axels years ago ,,never had any issues,,,

when you take your axels to the shop,,,dont forget to take your brake drums to get re drilled,,,
 
I have redrilled axles & drums on my 8 3/4 rear. I am not sure there is enough "meat" on the flange of the 7 1/4 to redrill. I will look later today.
You are incorrect about later rear assys. All 7 1/4 "A" body rears are the are width. So if you can find a later large bolt pattern "A" body rear, it is a bolt in swap. You cannot install late model LBP axles in the earlier SBP housing, the bearing size is different.
 
i welded and redrilled my sb 83/4 axles you just have to be careful on the orientation cuz when you weld them the flange gets really hard from the heat. i used carbide drills . they have been on my dart for 3 years now with no problems and im running a crate 360 420hp magnum with a 4 speed and 410s
 
go with #4 ,BUT I just did mine on my 66 dart and they had to slug the hole that you took the axle flange nuts off with. in order to give enough meat to have 1/2 inch screw in studs . one of the studs comes within 1/4 inch of the hole, now I have to put the nuts on using a wrench. no big deal since I just put on new bearings and won't have to touch it for a few years.

(edit) I had all the Drums from both the 9" and the 10" rear plus the axles plugged and the front hubs redrilled , all that cost me a total of 75.00. I did supply the screw in studs for all 4 hubs and axles.

the new bearings cost me more than getting the drilling conversion done. $121.00 =bearings and seals for front and rear. I just looked at a friends 7 1/4 LBP and it has just a little more meat than my redrilled axles and I can get the hole put back in for the flange nuts without weakening the stud locations.
 
moser axle will do it at a fair price and they say to use screw in studs
 
Have had a set that was redrilled in a dart behind a 340 for seven years and no problems.The last one That I had redrilled cost 75.00 for both.If that is too expensive,I have no other answer.
 
Charrlie_S said:
I have redrilled axles & drums on my 8 3/4 rear. I am not sure there is enough "meat" on the flange of the 7 1/4 to redrill. I will look later today.
You are incorrect about later rear assys. All 7 1/4 "A" body rears are the are width. So if you can find a later large bolt pattern "A" body rear, it is a bolt in swap. You cannot install late model LBP axles in the earlier SBP housing, the bearing size is different.
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Do this. No headaches when it comes time to replace drums, and I'm betting you can get a 7 1/4 for less than what your machine work will cost. Plus, no question about failures from redrilling or any of that. I'm betting you can get this axle for free or near it, and the cost of some brake fluid and 2-3 hours of work.

Edit, think about the cost of having to redrill drums if you ever have to replace 'em, too.
 
Well;I have a 7.25 late w big bolt,but you gotta come and get it
 
If you don't need the strength or a posi, I'd just go & find a late model 7 1/4 A body rear & install it as an assembly. Got to be a few of them out there in the junk yards or I'm sure a few members here would have one to sell. A lot less hassle than getting axles redrilled & welded & drums drilled & hoping there is enough material on the flanges. Probably cost you about the same anyway since it's not a desireable rear. I'm not sure the 7 1/4 axles have enough on them like the 8 3/4 does to be drilled.
 
I took a look at a 7 1/4 axle, today. There really isn't enough meat to just redrill the flange for the LBP. As another poster stated the hole in the flange to remove the axle flange nuts i the main problem. It really should be filled, then you have no convient way to remove the nuts.
Best to just get a LBP 71/4 "A" body rear.
 
#1 or#2 gets my vote. If the flanges were larger and there wasn't the big hole for a socket to go through so you could unbolt the axle it would be a lot simpler. If you want to keep the rear end, I would get new axles. You have already spent some dollars for the front. Spend a few more and get it done right. tmm
 
I don't see why your concerned... Your wheel isn't going to just "fly off". How about just changing the studs to grade 8, and call it a day? I could see wanting to convert over for some aftermarket rims, but your over-thinking it at this point.
 
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