70 Chevelle Performance Brake Upgrade Question: Wilwood AERO6 or PowerStop?

[jml890]

I have a 70 Chevelle that is a "done" running car. Key highlights include: 402ci BBC, TH400 transmission, TMI Products Interior, almost every Eddie Motorsports Billet product for the Chevelle, Holley Sniper EFI, Vintage Air, and other stuff not really worth mentioning. I am building a higher HP engine for it (roughly 461ci BBC with Brodix Aluminum RaceRite heads), therefore I need a bigger rear end. I just acquired a 12 bolt with a posi, and of course it came with drum brakes. I have held off on doing any other upgrades to the car simply because I know it'll turn into a giant snowball. Where my problems start is braking. I plan to eventually use the car in autocross events therefore I want a brake set up that can handle the demands of it. I will be running CPP's version of the C5/C6 corvette spindle (I simply cannot afford to spend the money of ATX's spindles at this point in time.) I currently have tubular arms, but the car will be changed over to all Speedtech components at a later time.

The options that I have been throwing around are:
- 2013 C6 Z06 Factory GM calipers - evidently, GM discontinued the front brake calipers with J56 RPO braking. I found out the hard way after being given a smoking price by my local GMC dealer on all of the parts (I have been purchasing parts from this dealer for years for independent shops and another dealership hence the smoking price). I said okay deal lets order it, only to be told oh... sorry the front calipers are no longer available. Red or Silver (I wanted silver).
- My next option which I am on the fence about because my source which I spend a lot of money with on a monthly basis was unwilling to budge on my price was, PowerStop C6 Z06 brake kit here is the link to the kit I am considering: https://www.powerstop.com/search/?part=KC1445-26
- Lastly, I am on the fence about Wilwood's AERO6 Front Caliper and Bracket Upgrade Kit for Corvette C5-C6, and Wilwood Rear Forged Narrow Superlite 4R Caliper and Bracket Upgrade Kit for Corvette C5-C6. Here are the links: https://www.wilwood.com/BrakeKits/Br...emno=140-12629 and https://www.wilwood.com/BrakeKits/Br...emno=140-14026

I know Wilwood has been around forever in the performance market, but I am skeptical about the quality of the part as a stock replacement product considering I will eventually be running the vehicle hard. I don't want brakes to be a weak link that will leave me irritated that I didn't do something else. I have seen several people in different forums talk about how great the GM Z06 calipers are, which is why I wanted to go that route (obviously that's no longer an option - I only want new, not used).

With everything mentioned above taken into consideration, I know I will be spending more money going the Wilwood route than I would doing PowerStop. Does anyone have any first hand legitimate experience with the above mentioned products that can steer me into a better direction? Please keep in mind cost is definitely an issue.

[jml890]

[65 drop top]

The wilwood kit you linked to has a piston area of 4.04” in the front. That isn’t the best caliper for manual brakes. So either you’d want to order those calipers with the 5.40” piston area, or add a booster. I didn’t see where powerstop lists their piston area, but you’d want to find out. I know this doesn’t answer your question directly, but something that’s definitely worth noting.

[jml890]

The wilwood kit you linked to has a piston area of 4.04” in the front. That isn’t the best caliper for manual brakes. So either you’d want to order those calipers with the 5.40” piston area, or add a booster. I didn’t see where powerstop lists their piston area, but you’d want to find out. I know this doesn’t answer your question directly, but something that’s definitely worth noting.

Thank you for the heads up on that. From the looks of it, every caliper that Wilwood offers for the C6 corvette uses a piston area of 4.04" for the front.

The biggest thing that I am aiming for in a brake system is 6 piston, fixed caliper (not floating). I am running manual brakes, no assist of any sort.

[65 drop top]

Thank you for the heads up on that. From the looks of it, every caliper that Wilwood offers for the C6 corvette uses a piston area of 4.04" for the front.

The biggest thing that I am aiming for in a brake system is 6 piston, fixed caliper (not floating). I am running manual brakes, no assist of any sort.

The factory C6’s would have had power brakes so that caliper would be appropriate for those cars. Wilwood can definitely upgrade you to the 5.40” calipers, and it should cost the same. Piston area is what will makes the car stop. The extra pistons just help with even pad wear and some other technical stuff. And one last thing, if you can find out your master cylinder size, that really needs to match the calipers. A little extra effort in planning will get you a really solid brake system.

[jml890]

The factory C6’s would have had power brakes so that caliper would be appropriate for those cars. Wilwood can definitely upgrade you to the 5.40” calipers, and it should cost the same. Piston area is what will makes the car stop. The extra pistons just help with even pad wear and some other technical stuff. And one last thing, if you can find out your master cylinder size, that really needs to match the calipers. A little extra effort in planning will get you a really solid brake system.

I actually went one step further and looked at all of the calipers Wilwood has for a 70 Chevelle, they show the same piston area. I am aware that the smaller bore size is better for manual brakes. The larger bore sizes is required for Hydro/Vacuum assisted brakes. The car currently has a 1" bore right now, I will probably have to step down to roughly a 7/8" bore (whichever Willwood offers).

I have absolutely no room for a vacuum booster(and they're ugly), and hydroboost isn't an option (I do not trust them). The brake kit I am purchasing is from a retailer not from Wilwood directly. After having some people swing by Power Stops booth at Sema yesterday, simply from a quality appearance stand point, I will not be using Power Stop brakes.

[65 drop top]

I don’t want to come off as a know it all or as a professional, I’m not, I’m just answering as a consumer who has spent several thousands on brakes to come up disappointed. 4.04” and manual brakes will give you brakes less satisfying than a mini van. Get the 5.40” Wilwoods or get a brake booster.

[jml890]

I don’t want to come off as a know it all or as a professional, I’m not, I’m just answering as a consumer who has spent several thousands on brakes to come up disappointed. 4.04” and manual brakes will give you brakes less satisfying than a mini van. Get the 5.40” Wilwoods or get a brake booster.

I do appreciate your feedback and experience. By no means to I intend to appear as though I am dismissing your experience with the calipers. I did discuss the potential issue further with Wilwood on Friday, I was assured that the issue like you mentioned is typically more severe on larger body cars such as Impalas. I was told that both the C6 Corvette and Chevelle use the same piston area, and that I need to run the 7/8" bore master as I had already figured.

I will give the 4.04" calipers a shot based upon the direction of Wilwood. They should be here on Thursday.

[MonzaRacer]

Kore3 and you can install BIG Corvette C6 brakes
And they will point you

[jml890]

Kore3 and you can install BIG Corvette C6 brakes
And they will point you

Thank you for the input. I actually have the brackets to mount my Wilwood calipers on my desk at work that I got from Kore3. Tobin is very helpful and friendly over there. My calipers should be arriving tomorrow.

Now I’m just trying to figure out the rotor situation, I don’t really want a 2 piece rotor, mostly because of price.

[MassMalibu]

Following up to see where you landed with your brakes?

I’m going through a similar setup with my 70 Chevelle and haven’t finalized. I have the Superlite 4R in the rear and would like the Aero6 in the front. I don’t see any other piston area options bigger than 4.04, as you mentioned. I contacted Wilwood and they’re not super helpful, but it sounds like a 7/8 Wilwood tandem master cylinder is the way to go with those calipers and a manual system.

Love your car by the way!

[65 drop top]

https://www.wilwood.com/Calipers/Cal...?subname=Aero6 Scroll down to the 6th caliper on that page. Wilwood doesn’t include the 5.40’s in the kits because they assume most will use power assist. They will sub out the 4.04’s with the 5.40’s in a kit at no charge.

[MassMalibu]

That’s great help. Thank you

Do you know if a 15/16 or 7/8 Wilwood master cylinder would work better with that caliper setup?

[65 drop top]

That’s great help. Thank you

Do you know if a 15/16 or 7/8 Wilwood master cylinder would work better with that caliper setup?

It would also really depend on pedal ratio. But with a roughly 6.25 or so ratio I believe the 15/16 is a good choice. There are some brake force calculators online, which would really give you the best answer.

[jml890]

Following up to see where you landed with your brakes?

I’m going through a similar setup with my 70 Chevelle and haven’t finalized. I have the Superlite 4R in the rear and would like the Aero6 in the front. I don’t see any other piston area options bigger than 4.04, as you mentioned. I contacted Wilwood and they’re not super helpful, but it sounds like a 7/8 Wilwood tandem master cylinder is the way to go with those calipers and a manual system.

Love your car by the way!

sorry, I completely stopped looking at this page after I bought everything.

I ended up getting the Wilwood aero6 Z06 calipers up front, FNSL4 c5 Z06 calipers in the back using kore3 brackets in the rear. I bought the cpp c5 style spindles and AC delco c7 ZR1 corvette hubs. It’ll all be 14” rotors.

I am actually installing it all this week in preparation for the 2023 west coast hot rod power tour. So far, the caliper bracket hits a spot on the spindle from CPP so I need to create a notch in the bracket on the mill to clear it.

Im doing my 12 bolt rear end swap on at the same time as switching the rear arms to UMI arms, along with speedtech front control arms with Viking hybrid coil overs.

[jml890]

Here are some photos of the front spindle, hub, rotor, and caliper going on. I am running the CPP c5 style spindle, and C5 ZO6 14" upgraded brakes. The caliper bracket interferes with the hub mounting flange slightly not allowing the bracket to mount to the spindle. I had to mill a small portion of the bracket for clearance purposes on both sides. Once the clearance was made on the bracket, it all went together with very minimal shimes. Lateral shimming was 3 of the thinest shims. Vertically only required the black spacer provided by wilwood to step from 13" rotor to 14" rotor. The pad is ever so slightly hanging over the friction surface of the rotor, which is so minimal that I am not worried about it.

Attached are some photos to show how its coming along. The rear UMI control arms showed up today so I can work on trying to swap the rear end and front end this weeked.

[jml890]