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I've got a 56 TF, a 12 bolt rear end w/ 6 lugs configuration. Who makes a reasonable disc brake conversion kit the changes the pattern to 5 x 4.75?

Might be cheaper to change the axle assembly. You'll be looking at changing the axle shafts to get the bolt pattern you want.
For brakes, check out late S-10 blazer 4 doors. They had rear disk with the bolt pattern you want.

Several of the big Fords have manly rear ends with the disk brakes on them... I saw a few at the local ecology wrecking yard.

pick a part a lincoln 8.8 rear end 62 inches wide go on 50% off day about $85.00. put the axles and redrill them chevy pattern.

LONGBOX55

Thanks for the tip. So if I understand your coment, I really won't need to change out the entire rear end, just find axles off a S-10.

I'll start down that path a nd see what I can find.

Thanks,

UH-OH, I think I might have mis-lead you. What I meant that if you change to the 5x4 3/4 bolt pattern, S-10 brakes would work, not that S-10 axle will fit your housing. John Romero has the right idea on axle shafts, though. You could have them re-drilled for the 5x4 3/4 pattern, or possibly get a set for a Chevelle/Camaro from the 70s. I don't know for certain if those will swap directly, but it might be worth looking at. If you could find a late 70s Trans Am many of them had Corvette disks on them with the 5x4 3/4 pattern, those might be somewhat hard to come by though.

CHANGE THE REAR END COMPLETELY ITS CHEAPER AND YOU CAN GET A NEWER REAR END WITH FREEWAY GEAR RATIO

John -

I'm leaning that way. I'd like to keep the 12 bolt, however I'm changing the front to IFS, so I'll most likey change the rear end out. Having a devil of a time finding a Camaro rear end in Colorado. I'll need to look through the rear end text here in the forum to find another donor possibility.

I HAVE A 66 WITH 6 LUG DRUM. I PULLED A REAREND YESTERDAY FROM 72 SUBURBAN C10 WITH 411 GEARS AND 5 LUG BOLT PATTERN, EVERTHING SEEMS TO BOLT RIGHT UP MY QUESTION IS A 411 GEAR A GOOD HIGHWAY GEAR???

No, 4.11 is not a good highway gear. Unless you have very tall tires. Use one of the gear calculators and determine what you need. Do a search for the gear calculator.

4.11s would be ok if you use an overdrive trans. My '85 S 10 has 4.11s with a TH 700R4 and 235/75/15 tires. it runs highway speeds just fine.

hi lonnie, well in my 66 c10 i've got a 1982 gmc 305 v8, the orignal 3 speed trans,and 6lug rearend. on the open highway my rpms are to high at 65 70 mph. i want to use the burban rearend because of the 5lug ???? what would be agood gear and can i find it in a boneyard???

Chris,

Picking the right gear ratio involves many variables. Choosing a rear axle also requires making some desisions as to bolt pattern and size of bolt pattern. I am not 100% positive about the burb bolt pattern, but I believe it is larger than the standard GM passenger car pattern. Unless you are going to swap the front axle with the later model parts, (Bolt in) you might consider using a passenger car axle. If you want to keep the 6 lug in the front you can get a K10 rear axle that should fit your truck, with the appropriate gear ratio.

There are many gear calculators on the web. You can do a search at www.hotrodders.com and find a list of some of them. Here is one I found by doing a Google search.

www.rocky-road.com/calculator.html

It is geared "no pun intended" to 4x4 use, but has many different calculators that will help you determine which wheel, tire, and gear ratio combination will work best for you. One last thing, as if there could ever be a last thing when working on old Chevy's, you need to consider the wheels you will be using on you truck. Will you be using stock, off the shelf custom or custom made wheels? Making these desisions now will help you choose which axle will work for you. One more last thing, see I told you there is never a last thing, if you have a stock rear axle in you C10, it is probably a higher ratio than the 4:11 ratio.

Chris, welcome to the BB, I hope my comments have helped and not confused you. Do some searches here, there are many posting on this subject.

Well, I just can't resist the temptation to give just one "last" bit of information. As LONGBOX55 said, you might want to use the 4:11 rear axle and change the transmission to an overdrive trans. A T-5 five speed would be a real nice choice.

Lonnie, you do bring up a good point on the bolt pattern. The '71-'72 1/2 tons have a 5x5" bolt circle that was used to the '98 model year. To get the front to match, the front spindles from a '73-'87 can be swapped in by using the later truck balljoints. That not only gets the 5 lug pattern, but also disk brakes. I'm hesitant to suggest a passenger axle because the '72 axle is an easy bolt in, where a passenger axle or 4x4 axle would require modification to fit the '66 suspension. If a passenger car axle is used, one could set it up like a Nascar stock car, they essentially use the '60-'72 rear suspension.

LONGBOX, you are right on. With the '66 the change over to later suspension component is very easy, and would make the most sense. The truck stays all truck with matching bolt patterns; all the while using off the shelf items.

Lonnie

thank's for the feed back. i will use the 72 burban 5 lug rearend with 4.11 gears. my next trip to the boneyard i'll get a t5 from a s10. i seen alot of them but only a couple that had 5 speed stick shift. as for the front 73-87 chevy truck will be the doner for my 5 lug disk brakes conversion.

Chris,

Sound like a good setup, good luck with you project.

Lonnie

Skraps, if camaro/firebird rears are scarce the mid size GM's (cutlass, chevelle, etc.) had rear ends in the 61" wide range. Just be sure to have full tanks on your cutting rig and a new grinding wheel to trim all the coil springs mounts, torque arm mounts, etc., etc., off these housings plus you'll have to weld on spring perches. The saving grace is they're dirt cheap and have a wide selection of ratios.

Another suggestion....Camaro IROC-z's (89 for sure) run a posi/disc in 3.08 and 3.42,5 lug, 4-3/4" pattern, 62" wide from backing plate to backing plate. The 3.08 goes behind 305 T5 combos so it's no wimp! I have non-power discs which work great! Replacement brake parts and seals are expensive but less than bolt-on conversions. I found the later model ABS diffs were very dear. Hope this helps.

Picked up a 78 Trans Am 273 posi this weekend. Very excited to have this piece of my plan in my garage. Want to change out the 272 gears for 308 or 343. I'll start cleaning and rebuilding it soon.

Thanks for all the assistance.

I lucked out on getting a 1981 trans am rear end with disc brakes and Im getting it ready to install it in my 51
good luck and have fun on yours !