in too deep: trying to go BBP on a 68 barracuda and its going.. poorly.

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machinecat

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Hi! First off, im new at all this. I wanted a muscle car project, and always loved barracudas. So.. i recently bought a 68 barracuda with a 318/auto thats been sitting for a while. The brakes are a mess, the tires are garbage, and its a 5x4 bolt pattern. I want to drive this thing in highway traffic, i want decent braking performance, and i want wheel and tire selection. I figured i might as well go to 5.4x5 as it shouldn't be too difficult, right?? The initial plan was buying a disc brake setup for the front, and leaving the drums in back. Sounded fairly doable. I bought the hells gate hotrods jig to drill the rears to fit 5x4.5, and also bought 5x4.5 wheels all round. Also a 5x4.5 front disc setup. So, i have all this crap in my garage now, and finally have a chance to start drilling. Anyway, today i discovered that the rear hubs have these big holes in them right where one of the bolts would be going. I also managed to break the pilot hole drill bit in the jig cause it caught the edge of the hole on the hub it was going into. So now what? Looks like i cant drill these after all, and will need new axles i guess?
BUT im not sure what i need for that to happen or what axles to get.
I have an 8 3/4 rear end, 714 carrier, which i believe means i have a 10 spline? which means i cant use the dr diff axles? also im not sure if this is the original rear end, from what i understand it might be. might.
moser sells a set i saw from elsewhere on here, will these work? A30-CST-A45 - A-Body, 8 3/4" Rear Axle Shafts, Stock A-Body Drum Brake (Redrilled) -- 30 (Pair) - Moser Engineering if so thatd be great, im hoping to re-use the rear drums. tryin to keep that budget down..

also i dont want spacers. rears are 15x8 with 245 tires, not sure it would fit on there with spacers.

So, anyone have an idea what i should do here? id prefer to keep it cheap as possible, i still have more crap i need to buy. i haven't even been able to drive it yet! it runs, so im hoping its fine. it wont be, but i can hope :)

attached are a few pictures, cause pictures are fun! it looks nice but its hiding all the rust :D
last pic is where i broke the drill bit on the hub trying to make new holes..

9D467150-907C-4A69-BAF1-7007C1A97653.jpeg

2DC4447E-D912-4D94-AE1E-12C4FA08EA08.jpeg

IMG_6492.jpeg
 
I don't want to write a book but here goes

After market axles will work in all 3 carriers. 741 , 742 , 489. Green bearings the axles will not use bearing adjusters so the axles will have to be trimmed to fit if they are to long.

Also BBP axles when used you will need the BBp backing plates, BBp Drums, BBp park brake struts and BBp brakes,


If drilling your axles ? You need to put the fixture on the axle turn it clockwise until the lug hole in the fixture sees the large hole in the axle and mark the axle, then turn it counter clockwise until you see a lug hole in the axle and mark the axle. Move the fixture back until you are a the center of your marks. This is where you drill for the new studs. Drill and tap the axles for 1/2 20 race studs. This will leave more room for the holes to be drilled.

Remember when using your small bolt axles with BB wheels you will need to use 3/8 spacers to keep the tires from hitting the leaf springs.
 
You got a long way to go and being so picky about chit that don't matter is screwing you up. Buy adapters and different wheels if need be. Move on.
 
First you need to inspect what you have to order the correct parts. If it is a stock a body 8 3/4 it will measure 52 5/8 inches on end to end of axle housing so take your axles out and remove the drums and backing plates and measure. If it is this size, then purchased Dr diffs stock A body axles, your 3rd member should have 30 splines for the axles. you will need to upgrade the rear drums and backing plates, brakes to 10X2.5 size. you will need to choose what type of rear axle bearing you wat to use, sealed green or factory tapered, because it will matter if you need to remove the spacer between the axles in the 3rd member on the green bearings. I'm sure you will hear various other options. enjoy the car.
 
i highly doubt someone custom ordered axles just to fit a center section in that thing. pull an axle and see exactly what you have.

if it were me i wouldn't waste the time re-drilling small bolt axles.. grab a set of dr. diff axles and then big bolt drum brakes. i have 11X2" drums on the back of our dart. they have worked very well for many years..
 
First off, if it's going poorly, you're doing it wrong. This has been done and done easily for decades. You should have done research first, instead of after, then you'd be well educated on what to do. These cars aren't Chevys. They're a little different and require a different approach. I second the Dr Diff recommendation. Cass is a great guy. If anyone can help you make chicken salad out of chicken ****, he's your guy. Looks like you have a nice car. Maybe next time you tackle a project on it, you'll do your research first. It might save you a lot of trouble.
 
All 8 3/4” axles are 30 spline, so your reference to the 10 spline count is in the yoke, which has no bearing on your axle change. I doubt it’s a 10 spline yoke anyway on a 741 case. Changing to BBP axles is as easy as buying the axles with the correct offset to use BBP 10” brakes. What you use for bearings on the axles is up to you, I believe you can buy them with tapered bearings and use your old races, or with green bearings. Your choice. When buying the brakes, try to get a complete set from your donor source, as there are different shoe widths, and you need the corresponding backing plates for the width your are buying. You’ll get it, just take a couple shots of patience before you head back out to the garage.
 
ok dr diff 30 spline and green bearings it is. theres a lot of info out there and its not always easy to put it all together in a way that made sense.. go easy on me ok :D im just trying to get it running and driving without spending my whole budget. i went with drilling as it seemed like a good idea at the time and would let me keep the brakes. the jig only goes on one way, so im not sure what the deal there was.

anyway thanks for clearing up the axle cosgig!
 
machinecat said:
ok dr diff 30 spline and green bearings it is. theres a lot of info out there and its not always easy to put it all together in a way that made sense.. go easy on me ok :D im just trying to get it running and driving without spending my whole budget. i went with drilling as it seemed like a good idea at the time and would let me keep the brakes. the jig only goes on one way, so im not sure what the deal there was.

anyway thanks for clearing up the axle cosgig!
Click to expand...
Don't mind some of these guy's, some of them are older than dirt and crusty
They will help a guy out and give him a little crap along the way.
I'm sorta that way.
 
I also make 5 x 4.5" bolt pattern A-body 8.75" axles that re-use original (re-drilled) 5 x 4" bolt pattern brake drums ($298 pair assembled).
 
machinecat said:
Hi! First off, im new at all this. I wanted a muscle car project, and always loved barracudas. So.. i recently bought a 68 barracuda with a 318/auto thats been sitting for a while. The brakes are a mess, the tires are garbage, and its a 5x4 bolt pattern. I want to drive this thing in highway traffic, i want decent braking performance, and i want wheel and tire selection. I figured i might as well go to 5.4x5 as it shouldn't be too difficult, right?? The initial plan was buying a disc brake setup for the front, and leaving the drums in back. Sounded fairly doable. I bought the hells gate hotrods jig to drill the rears to fit 5x4.5, and also bought 5x4.5 wheels all round. Also a 5x4.5 front disc setup. So, i have all this crap in my garage now, and finally have a chance to start drilling. Anyway, today i discovered that the rear hubs have these big holes in them right where one of the bolts would be going. I also managed to break the pilot hole drill bit in the jig cause it caught the edge of the hole on the hub it was going into. So now what? Looks like i cant drill these after all, and will need new axles i guess?
BUT im not sure what i need for that to happen or what axles to get.
I have an 8 3/4 rear end, 714 carrier, which i believe means i have a 10 spline? which means i cant use the dr diff axles? also im not sure if this is the original rear end, from what i understand it might be. might.
moser sells a set i saw from elsewhere on here, will these work? A30-CST-A45 - A-Body, 8 3/4" Rear Axle Shafts, Stock A-Body Drum Brake (Redrilled) -- 30 (Pair) - Moser Engineering if so thatd be great, im hoping to re-use the rear drums. tryin to keep that budget down..

also i dont want spacers. rears are 15x8 with 245 tires, not sure it would fit on there with spacers.

So, anyone have an idea what i should do here? id prefer to keep it cheap as possible, i still have more crap i need to buy. i haven't even been able to drive it yet! it runs, so im hoping its fine. it wont be, but i can hope :)

attached are a few pictures, cause pictures are fun! it looks nice but its hiding all the rust :D
last pic is where i broke the drill bit on the hub trying to make new holes..
Click to expand...

It would have been a lot easier and cheaper to keep the small bolt pattern axles and brakes. If you have an 8 3/4 rear they are good for 400,000 miles with only lube changes. You can get premium brake shoes from Firm Feel and have good braking and change nothing, assuming you have 10 in drum brakes all around. I have been through this too many times back and forth with my own cars. The 66 and 68 Barracudas have 5 on 4.00 bolt circle 8 3/4 rears, Kelsey Hayes front disc brakes, and 15" wheels. My brothers 67 Barracuda has the 5 x 4.50 bolt circle and there is a lot of time and money to get it right. Maybe get good tires and custom wheels with the money you save...
 
on measuring backing plates to determine what size shoes go on it, oldkimmer gave me these dimensions some time ago. so far it has worked for me. lay backing plate on bench, face up. you will have to let the gig dimple on rear hang off bench, so the backing plate rests on the rear lip. measure down to the bench thru the center hole and if measurement is 1.5 inches=11x2. if 1.75 inches=11x2.5. if 2 inches=11x3. credit oldkimmer for this. i will take pics later to show how i do it.
 
Oldmanmopar said:
Learned something new again today. I did not know this. Do you have rotors to replace the 4 inch small bolt front rotors?
Click to expand...
I don't list 5 x 4.5" bolt pattern axles which require re-drilling the drums on my web-site, but they are in stock.

I don't carry 5 x 4.5" bolt pattern conversion front rotors.
 
Oldmanmopar said:
I don't want to write a book but here goes

After market axles will work in all 3 carriers. 741 , 742 , 489. Green bearings the axles will not use bearing adjusters so the axles will have to be trimmed to fit if they are to long.

Also BBP axles when used you will need the BBp backing plates, BBp Drums, BBp park brake struts and BBp brakes,


If drilling your axles ? You need to put the fixture on the axle turn it clockwise until the lug hole in the fixture sees the large hole in the axle and mark the axle, then turn it counter clockwise until you see a lug hole in the axle and mark the axle. Move the fixture back until you are a the center of your marks. This is where you drill for the new studs. Drill and tap the axles for 1/2 20 race studs. This will leave more room for the holes to be drilled.

Remember when using your small bolt axles with BB wheels you will need to use 3/8 spacers to keep the tires from hitting the leaf springs.
Click to expand...
Steve, you NEED to write that book. Even if it's scribbled notes and an outline LOLOL
 
Oldmanmopar said:
I don't want to write a book but here goes

After market axles will work in all 3 carriers. 741 , 742 , 489. Green bearings the axles will not use bearing adjusters so the axles will have to be trimmed to fit if they are to long.

Also BBP axles when used you will need the BBp backing plates, BBp Drums, BBp park brake struts and BBp brakes,


If drilling your axles ? You need to put the fixture on the axle turn it clockwise until the lug hole in the fixture sees the large hole in the axle and mark the axle, then turn it counter clockwise until you see a lug hole in the axle and mark the axle. Move the fixture back until you are a the center of your marks. This is where you drill for the new studs. Drill and tap the axles for 1/2 20 race studs. This will leave more room for the holes to be drilled.

Remember when using your small bolt axles with BB wheels you will need to use 3/8 spacers to keep the tires from hitting the leaf springs.
Click to expand...

SBP brake bars and parking brake struts work just fine with BBP brakes, as long as they’re for 10” brakes. Backing plates, drums and shoes don’t interchange.

E-Brake help please

Whether or not spacers will be needed depend entirely on the size of the wheel, backspace, and tire being used. SBP axles and BBP axles do have a different flange offset that increases the rear track width when converting to BBP axles with the factory offset.

77221140-E312-43B8-BEBB-DCC15913BE3E.jpeg
 
My opinion: You are wasting time and money. SBP is just fine for most. They made millions of cars with SBP. For all the money you have spent, you could have bought a really nice set of SBP wheels and you could have moved on to something else.
 
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