OK time for a new rear end suggestions

[Nativefx]

Well I got my correct rear Forgeline wheels in and had the tires mounted. It's now time for me to pull out the stock rear in my 69 Firebird and start fitting the 19 x 11.5 wheels with 325/30/19 Pilot Super Sports inside the Alston mini tubbed rear. So my next purchase will obviously be a new shortened rear end and I'm hoping I can get some help in deciding what to go with (12 bolt, 9") possible gearing options and differential (tru track, wavetrack, etc)? Is it worth considering a floating rear end and if so what would be the best bang for the buck?

Obviously I dont' have much knowledge about a lot of this, so maybe it would be a good idea share some of the things I do know, or at least have a fairly good idea about.

So here's some information about my setup:

Ridetech Level 2 AirRide
Motor will be swapped out later for a LS3 - roughly 480-500hp depending on cam choice (GM Hot Cam or LS7 cam, possibly others)
Trans will be swapped for T56 Magnum (thinking close ratio would be best?)
Tire size as mentioned 325/30/19 - can't remember what that calculated out to for overall height?
Front brakes are Baer Pro+ 14" so was hoping to possible match for the rear. Is this possible with a floater rear end option?

This car will be mainly a street car, but I would like the option of one day maybe doing some road racing and/or autox. Probably not a lot, so mostly street driven. Although I want it to be fun around town, i'm building this car as a driver and anticipate taking it out on a few road trips, so it would be great when considering the rear gearing to hear some thoughts on that. Right now I'm leaning towards 3.73 or 3.40. I'm still trying to read up on that aspect in relation to the T56 I go with.

I'm open to hear as many suggestions as people have, as at least I still have some flexibility in my overall setup since I haven't yet sourced the trans and motor, but I do have a pretty good idea of what it will be.

If I've let out any information necessary to provide, please let me know.

[MillerBuilt]

Right, wrong, indifferent. I like both the 12 bolt & 9".
Both are more than capable.

If you choose to stay "semi-floater" then make sure you use the Big Ford "New Style" (aka Torino) flange end on either one. Especially since you do not currently have a rear brake kit and could order one for that particular flange pattern...

I chose a Strange Engineering 9" and will be going with a 3.89 gear with a 35 spline TruTrac that should work fine with my T-56 Mag (w/2.66 1st/.63 6th).

As for floaters, I think they are a great choice if you really need them (plan on Auto-X / Road Race). But not all are ready to go "out of the box". Many/most will require you to retrofit different parts/pieces from different sources for the brake caliper/rotor & parking brake of your choice to work. This may or may not be a deterrent depending on your resources/fab skills. Most of these type floaters will also keep the caliper offset far towards your frame and will not obtain the same look as the front if that matters to you...

BAER seams to have the closest thing to a "street friendly" (with park brake) full floater right out of the box, but you will be limited to only their caliper/rotors and will not be a maintenance free setup and will require some level of know how/knowledge to monitor. Not difficult and outa all fairness so do all the others, but just cant install it and never look back that's all...

For me, I am going to be running my own "floater" set-up https://lateral-g.net/forums/showthread.php4?t=48782 . I think is a great balance of everything. Reap the benefits of a full floater, purchase all components at any Chevy Dealership, Run ANY brake manufacturer you want that offers a brake kit for a C5/6 Corvette. Oh, and minimal to no maintenance when compared to ALL other floaters.

Hope this helped.

Jay

[Ron Sutton]

Jay offered some excellent, objective advice. Love it.

Ron Myers has a similar semi-floater rear end housing utilizing the C6 bearing/hub ends & we're using it in an offset 3-link install. I like it. I don't know what it costs, but it puts better bearings on the outer ends of the housing for safety reasons. While they're not as heavy duty as the bearings in floater ends, they are a nice step up from the regular roller bearings in 12-Bolts & 9" Fords. Plus they only require occasional inspection for play (wear) & basically no maintenance.

For ultimate safety and the elimination of any brake knock back, a full floating rear end is tops. They use two opposing tapered roller bearings inside a beefy hub that are rated over 2000# each for thrust load. Most of the hard runners in autocross and/or track days have gone this route, or want to. Surprisingly, the cost is a not a lot more when compared to buying a flange axle housing. A complete Speedway Engineering floater rear end housing with axles, hubs, drive plates, bearings, studs, etc is $1299. This is does not include the 3rd member. Moser & Currie offer them for less, but I'm not a fan of the components they use. But if you're on a super tight budget, a complete floater from them is around $950 & better than going with a flange axle & single roller bearing.

Rear brakes were a challenge, but no more. Speedway, Moser & Currie all offer brakes and/or mounts installed ... but only up 12.19" rotors & no parking brake. Wilwood offers a nice street kit for the Speedway Mod-Lite Floater with 12.88" x .81" rotors & parking brakes. These do mount closer out to the wheel for appearance sake. The standard caliper only has 1.96" piston area, but can be upgraded to 2.46" piston area for no charge (requires the thicker pad). The rotor is the medium duty GT version and can not be upgraded to the Spec-37. So think "medium duty" here. I feel it is an excellent brake package for most Pro-Touring cars running autocross often & only occasional track days.

For my clients with a higher priority on performance, we don't run parking brakes for several key reasons.
#1 is they add a LOT of weight in exactly the wrong place ... as the parking brake hat/drum is cast iron ... out at the end of the axle housing. For those that are not familiar with the unsprung weight concept on solid axles, lighter components out on the end of the axle allow the shocks & suspension to respond quicker = more grip. Heavier components out on the end of the axle make the shocks & suspension respond slower = less grip.
#2 is the internal drum style parking brake creates additional friction, drag and heat that we don't want on a performance vehicle.

A trick my clients do, instead of running a parking brake, is to install a drag race style "line lock" solenoid in the brake line (front or rear - doesn't matter) with a regular switch instead of a momentary switch. When the car is parked & the engine if off, they simply leave the car in 1st gear (or park for autos) and the car isn't going to roll away. But they like to let the engine warm up at times ... so they start the car, put it in neutral ... press the brake pedal to apply brake pressure & flip the switch. Viola ... brakes are on. Then they can get out & let the engine run & warm up.

So I created brake kits for floater rear ends that don't have parking brakes, but do use rear racing brake parts like big, race quality brake rotors & calipers. The most common package uses a 13.06" x 1.25" Wilwood Spec-37 rotor and 4-piston Superlite caliper with either 2.46" or 3.00" piston area for serious braking force. These do place the caliper & rotor farther inward, so the appearance doesn't match the fronts. I plan to offer floater brake packages with 14.00" x 1.25" rotors and Aerolite 4P calipers once Wilwood offers the Aerolite 4P in a piston area in the 2.46"-3.00" range.

------------------------------------------------

Regardless of brand, version or source, I personally hope everyone driving their cars hard in autocross & track days go the floater route for both safety sake & the elimination of brake knock back ... which can also be a safety issue.

[Flash68]

Originally Posted by Ron Sutton

A trick my clients do, instead of running a parking brake[/B], is to install a drag race style "line lock" solenoid in the brake line (front or rear - doesn't matter) with a regular switch instead of a momentary switch. When the car is parked & the engine if off, they simply leave the car in 1st gear (or park for autos) and the car isn't going to roll away. But they like to let the engine warm up at times ... so they start the car, put it in neutral ... press the brake pedal to apply brake pressure & flip the switch. Viola ... brakes are on. Then they can get out & let the engine run & warm up.

Very cool idea, Ron.

[intocarss]

Originally Posted by Ron Sutton

[COLOR="Blue"]A trick my clients do, instead of running a parking brake, is to install a drag race style "line lock" solenoid in the brake line (front or rear - doesn't matter) with a regular switch instead of a momentary switch. When the car is parked & the engine if off, they simply leave the car in 1st gear (or park for autos) and the car isn't going to roll away. But they like to let the engine warm up at times ... so they start the car, put it in neutral ... press the brake pedal to apply brake pressure & flip the switch. Viola ... brakes are on. Then they can get out & let the engine run & warm up.

I've liked this idea for years, but was always warned against it. I was told the pressure could bleed off if the car sits for a long while. IMO if the system is sealed it could not bleed off but others disagree, Your thoughts??

[Nativefx]

Just read through your link.................

I really DON'T know much about rear ends! May have to read more info to make sure I'm understanding everything, and I KNOW I'll need to find someone who can fabricate whatever I'll need.

I add more comments below as I also "quoted" the post from Ron. Some of these comments are in regards to you product offering and things Ron touched on as well. I'm really hoping I can get some of this figured out, as I have my rear wheels now and need to pull the stock rear end. My other issue to deal with is setting up the mounting on the new rear end for my Ridetch set-up, but MCB told me I can get another set of mounts when I got to this point.

Originally Posted by JSM

Right, wrong, indifferent. I like both the 12 bolt & 9".
Both are more than capable.

If you choose to stay "semi-floater" then make sure you use the Big Ford "New Style" (aka Torino) flange end on either one. Especially since you do not currently have a rear brake kit and could order one for that particular flange pattern...

I chose a Strange Engineering 9" and will be going with a 3.89 gear with a 35 spline TruTrac that should work fine with my T-56 Mag (w/2.66 1st/.63 6th).

As for floaters, I think they are a great choice if you really need them (plan on Auto-X / Road Race). But not all are ready to go "out of the box". Many/most will require you to retrofit different parts/pieces from different sources for the brake caliper/rotor & parking brake of your choice to work. This may or may not be a deterrent depending on your resources/fab skills. Most of these type floaters will also keep the caliper offset far towards your frame and will not obtain the same look as the front if that matters to you...

BAER seams to have the closest thing to a "street friendly" (with park brake) full floater right out of the box, but you will be limited to only their caliper/rotors and will not be a maintenance free setup and will require some level of know how/knowledge to monitor. Not difficult and outa all fairness so do all the others, but just cant install it and never look back that's all...

For me, I am going to be running my own "floater" set-up https://lateral-g.net/forums/showthread.php4?t=48782 . I think is a great balance of everything. Reap the benefits of a full floater, purchase all components at any Chevy Dealership, Run ANY brake manufacturer you want that offers a brake kit for a C5/6 Corvette. Oh, and minimal to no maintenance when compared to ALL other floaters.

Hope this helped.

Jay

[Nativefx]

Ron, as mentioned above I still feel I'm a little overwhelmed with all the information, options, can/can't do options, etc. I am interested in learning more about both Jay's option and the option you mention below for a floater set-up. Although I may not "need" a floater set-up at the moment, if I decide I want to track the car/autox at some point, I don't want to have to reconfigure the rear end/brake set-up all over again due to problems with the flanged end type set-up. Brake knock back is definitely something I don't want to deal with.

I know I want to stay with the same Baer brake set-up as the front, which I think they only offer 13" & 14" rotors so I'm not sure how much this will limit my choices. I am interested in the "line lock" solenoid option for a parking brake, as long as there aren't any concerns as pointed out above?

Originally Posted by Ron Sutton

Jay offered some excellent, objective advice. Love it.

Ron Myers has a similar semi-floater rear end housing utilizing the C6 bearing/hub ends & we're using it in an offset 3-link install. I like it. I don't know what it costs, but it puts better bearings on the outer ends of the housing for safety reasons. While they're not as heavy duty as the bearings in floater ends, they are a nice step up from the regular roller bearings in 12-Bolts & 9" Fords. Plus they only require occasional inspection for play (wear) & basically no maintenance.

For ultimate safety and the elimination of any brake knock back, a full floating rear end is tops. They use two opposing tapered roller bearings inside a beefy hub that are rated over 2000# each for thrust load. Most of the hard runners in autocross and/or track days have gone this route, or want to. Surprisingly, the cost is a not a lot more when compared to buying a flange axle housing. A complete Speedway Engineering floater rear end housing with axles, hubs, drive plates, bearings, studs, etc is $1299. This is does not include the 3rd member. Moser & Currie offer them for less, but I'm not a fan of the components they use. But if you're on a super tight budget, a complete floater from them is around $950 & better than going with a flange axle & single roller bearing.

Rear brakes were a challenge, but no more. Speedway, Moser & Currie all offer brakes and/or mounts installed ... but only up 12.19" rotors & no parking brake. Wilwood offers a nice street kit for the Speedway Mod-Lite Floater with 12.88" x .81" rotors & parking brakes. These do mount closer out to the wheel for appearance sake. The standard caliper only has 1.96" piston area, but can be upgraded to 2.46" piston area for no charge (requires the thicker pad). The rotor is the medium duty GT version and can not be upgraded to the Spec-37. So think "medium duty" here. I feel it is an excellent brake package for most Pro-Touring cars running autocross often & only occasional track days.

For my clients with a higher priority on performance, we don't run parking brakes for several key reasons.
#1 is they add a LOT of weight in exactly the wrong place ... as the parking brake hat/drum is cast iron ... out at the end of the axle housing. For those that are not familiar with the unsprung weight concept on solid axles, lighter components out on the end of the axle allow the shocks & suspension to respond quicker = more grip. Heavier components out on the end of the axle make the shocks & suspension respond slower = less grip.
#2 is the internal drum style parking brake creates additional friction, drag and heat that we don't want on a performance vehicle.

A trick my clients do, instead of running a parking brake, is to install a drag race style "line lock" solenoid in the brake line (front or rear - doesn't matter) with a regular switch instead of a momentary switch. When the car is parked & the engine if off, they simply leave the car in 1st gear (or park for autos) and the car isn't going to roll away. But they like to let the engine warm up at times ... so they start the car, put it in neutral ... press the brake pedal to apply brake pressure & flip the switch. Viola ... brakes are on. Then they can get out & let the engine run & warm up.

So I created brake kits for floater rear ends that don't have parking brakes, but do use rear racing brake parts like big, race quality brake rotors & calipers. The most common package uses a 13.06" x 1.25" Wilwood Spec-37 rotor and 4-piston Superlite caliper with either 2.46" or 3.00" piston area for serious braking force. These do place the caliper & rotor farther inward, so the appearance doesn't match the fronts. I plan to offer floater brake packages with 14.00" x 1.25" rotors and Aerolite 4P calipers once Wilwood offers the Aerolite 4P in a piston area in the 2.46"-3.00" range.

------------------------------------------------

Regardless of brand, version or source, I personally hope everyone driving their cars hard in autocross & track days go the floater route for both safety sake & the elimination of brake knock back ... which can also be a safety issue.

[71RS/SS396]

If you want to stay with the Baer brakes they also make a floater option that has parking brake provisions and uses a aluminum backing plate so it doesn't add a bunch of additional weight. if you don't want to deal with pad knockback or leaks, go with a floater and be done with it. I've been using the Baer floater in my car for 4 years now and have had zero issues with it.
I would recommend a tru-trac for your intended use, I tried using the wave-trac initially in my car and liked the way the car turned with it, but it just wasn't very durable.

[Ron Sutton]

Originally Posted by 71RS/SS396

If you want to stay with the Baer brakes they also make a floater option that has parking brake provisions and uses a aluminum backing plate so it doesn't add a bunch of additional weight. if you don't want to deal with pad knockback or leaks, go with a floater and be done with it. I've been using the Baer floater in my car for 4 years now and have had zero issues with it.
I would recommend a tru-trac for your intended use, I tried using the wave-trac initially in my car and liked the way the car turned with it, but it just wasn't very durable.

Tim, great to hear some feedback from a guy running the Baer floater hard. I'm a Baer dealer but didn't know anyone running their floater. Did you have a local shop cut & weld the Baer ends on for you?

[MillerBuilt]

Originally Posted by Nativefx

Just read through your link.................

I really DON'T know much about rear ends! May have to read more info to make sure I'm understanding everything, and I KNOW I'll need to find someone who can fabricate whatever I'll need.

I add more comments below as I also "quoted" the post from Ron. Some of these comments are in regards to you product offering and things Ron touched on as well. I'm really hoping I can get some of this figured out, as I have my rear wheels now and need to pull the stock rear end. My other issue to deal with is setting up the mounting on the new rear end for my Ridetch set-up, but MCB told me I can get another set of mounts when I got to this point.

Yes, does get a little complex. And I will concur with the incredibly knowledgeable Ron (for what its worth cuz Im nobody ) in that a "traditional" full floater (Moser, Speedway, etc.) is hands down a stronger/lighter system simply due to the dual tapered bearing design and its being lighter mainly due to its lacking an emergency brake system.
BUT,,, is GM's/SKF's C6 ZR1 or C7 hub like I utilize in my offering strong enough? Mark Stielow seams to think/prove so...

And although it does add some pounds for adding the luxury of having an actual emergency brake (not park brake, but an actual emergency brake,,,, BIG difference), I personally would say weight well added to gain the benefits/street-ability/track performance at the level of a C6 Corvette!

With that said, I have been a BIG fan of dual tapered bearing designs for years and have quite a bit of hands on experience with them as well, and unquestionably are strong/light/great/proven AND are the best choice for "Track Cars" that spend most of their time at tracks,,,, BUT lack what is required for a "true" street car/daily driver IMO.

Although you can add spot calipers, line locks, valves, etc. NONE of these are considered an emergency brake and will do nothing for you should you have a brake failure while actually driving/racing and are not really a street/daily driver solution IMO. I think the word is "compromise" that would be appropriate when making the decision which is best for your car.

Jay