Discussion Forum - Northstar Chevelle Club

Lost in the 60s · President

RE: Out with the old

jim larson · 2K+ Club

Just a note, Chevy use to have disc brakes on the back of their Silverado for a while . Now they have gone back to drum brakes on the back of my 2009 silvarado.

jim larson · 2K+ Club

Lost in the 60s wrote:
67ss wrote:
If you really want to upgrade the rears instead of looking at discs I would look into the 11" drum upgrade instead. Much cheaper overall and you don't have to change master cylinders or pressure bias.
I have accumulated the parts to do this on my 66 when I finally get the 12 bolt. But Master power brake sells a complete kit instead of trying to piece things.
I thought about this last winter, while the car was apart but never followed up on it. I just went to their website and a kit would be easy but $500 is a bit steep for the budget. Can you shoot me a list of cars that I can scrounge the backing plates off of ? I would replace all the other pieces anyway.
Thanks

A few guys on Team Chevelle have up-graded the rears to 11".

Lost in the 60s · President

jim larson wrote:
Just a note, Chevy use to have disc brakes on the back of their Silverado for a while . Now they have gone back to drum brakes on the back of my 2009 silvarado.
My 2000 has rear discs and the pads still look new with 100k on them. That's why Chev discontinued them. They had more issues with the pistons seizing from little movement than it was worth. I can tell they are working when I have the boat and lately, the car, on a trailer.

67ss · 1K+ Club

Mitch my backing plates came off an 1989 caprice cop car. I am pretty sure GM still makes the backing plates brand new. Call Bryan, I had him look them up awhile back and he said he could get them. You then need to order drums for a 1973 chevelle wagon to get the correct bolt pattern as the caprice is 5x5.

Lost in the 60s · President

Would a '73 Chevelle wagon have the right backing plate too ? Kinda looking to get used to save money.

67ss · 1K+ Club

Yea the 73 chevelle wagon has the bigger brakes I don't know for sure al the years that do or don't though. I would imagine any caprice of the late 80's that was a cop car or taxi would have them.

The backing plate part number is 18002392 and they are still available at about $50.00 a piece.

Lost in the 60s · President

67ss wrote:
Yea the 73 chevelle wagon has the bigger brakes I don't know for sure al the years that do or don't though. I would imagine any caprice of the late 80's that was a cop car or taxi would have them.
The backing plate part number is 18002392 and they are still available at about $50.00 a piece.
Thanks, Chris. I did a search on car-part.com last night for a '73 wagon brake drum and it came up with several models that interchanged. One was a '77 only Monte Carlo. What year was that Monte that you got the wheels from ??
I'm thinking that for $100 just for the backing plates new, I can find used and buy all new internals for about the same cost. I have 3 cars that I would like to do this on too...

SShink · 3K+ Club

Had a blast on the test drive today with Dashboard!

He's driving the Elky like his 2009 Mustang now instead of an 'old guy' slushing through a 4 speed!

That combo is very happy cruising along at 75 mph only running just over 2K rpm. And, it didn't have any problem leaving from a complete stop. I'm sure Kevin you'll be very happy with the combo.

Now I know I need to swap out the 4.11's for higher gears since I'm just not happy crusing at 65 mph at 2500 rpm... Anyone interested in a well working 4.11 gear set with a Series 4 posi?

Bungy L-76 · Active Member

67ss wrote:
If you really want to upgrade the rears instead of looking at discs I would look into the 11" drum upgrade instead. Much cheaper overall and you don't have to change master cylinders or pressure bias.
I have accumulated the parts to do this on my 66 when I finally get the 12 bolt. But Master power brake sells a complete kit instead of trying to piece things.

Have you checked the backing plate bolt pattern with your rear?

The reason I ask is, I too got some 11" backing plates from a mid 80s Caprice and the bolt pattern is different then my 64 axle. I think this is because the Caprice had an 8.5" rear and my 64 is an 8.2" rear.

I did get a set at u pull it from a 65 Bel-Air that has 11" rear drums, and the backing plate bolt pattern matched my 64 axle. (I also used the 73-76 Chevelle drums)

jim larson · 2K+ Club

SShink wrote:
Had a blast on the test drive today with Dashboard!
He's driving the Elky like his 2009 Mustang now instead of an 'old guy' slushing through a 4 speed!
That combo is very happy cruising along at 75 mph only running just over 2K rpm. And, it didn't have any problem leaving from a complete stop. I'm sure Kevin you'll be very happy with the combo.
Now I know I need to swap out the 4.11's for higher gears since I'm just not happy crusing at 65 mph at 2500 rpm... Anyone interested in a well working 4.11 gear set with a Series 4 posi?

You much have large diameter tires. I have 27.2" diameter tires and a 3.31 with a 1:1 in 4th and Iam at about 2650 @ 65mph.

67ss · 1K+ Club

I happen to have some backing plates I know came off a 12 bolt. Taking some quick measurements they look to be the same. Not sure why yours did not seem to match? I know the caprice mine came from was an 8.5 rear end. I stole the posi and gears to install into the rear end on my buddies 55.

SShink · 3K+ Club

jim larson wrote:
SShink wrote:
Now I know I need to swap out the 4.11's for higher gears since I'm just not happy crusing at 65 mph at 2500 rpm... Anyone interested in a well working 4.11 gear set with a Series 4 posi?
You much have large diameter tires. I have 27.2" diameter tires and a 3.31 with a 1:1 in 4th and Iam at about 2650 @ 65mph.

Jim, I have an automatic trans with Over Drive with a 4th gear ratio of 0.67:1. That equates to a final gear ratio of 2.75:1 (4.11 X 0.67).

My tires are 25.75" tall installed on the car. Kevin and I double checked that today. Even with the OD, the 4.11 gears are just too deep for my liking. My plan this spring was to get the trans installed with the 4.11's that were already installed, and see how I liked it. The rpm is higher than I want on the highway.

Lost in the 60s · President

Do you have 235's on the rear ??? That is a short tire. The 275X60's on my car are 28" tall. Be a whole lot cheaper to get a pair of taller tires first and see if that's enough. Now if you were closer, I'd say try mine and see...

dashboard · 2K+ Club

SShink wrote:
Had a blast on the test drive today with Dashboard!
He's driving the Elky like his 2009 Mustang now instead of an 'old guy' slushing through a 4 speed!

Slushing? What does slushing mean?

I seem to remember back in the day we would call Powerglides, slush boxes. I thought the name slush box just carried forth to Powerglides bigger brothers Turbo and Hydro.

It was a fun run, thanks for riding along Stan 38 miles cruising at 70-80 and no trany leaks. Now I need to fix the vent window noise that I never heard before.

dashboard · 2K+ Club

Lost in the 60s wrote:
Do you have 235's on the rear ??? That is a short tire. The 275X60's on my car are 28" tall. Be a whole lot cheaper to get a pair of taller tires first and see if that's enough. Now if you were closer, I'd say try mine and see...

Stan, just recheck the math at 28 inchs.

SShink · 3K+ Club

dashboard wrote:
Lost in the 60s wrote:
Do you have 235's on the rear ??? That is a short tire. The 275X60's on my car are 28" tall. Be a whole lot cheaper to get a pair of taller tires first and see if that's enough. Now if you were closer, I'd say try mine and see...
Stan, just recheck the math at 28 inchs.

Kevin, thanks for letting me derail your post...

Mitch, I have 255/60/15's on the rear, and when we measured them, they were just under 26" inches while on the car. I'm sure that is making the gear ratio even deeper.

So here's the scoop:

With 4.11 gears and a 25.7" tire at 70 mph according to the Randy's Ring & Pinion Calculator = 2633 rpm

With a 28" tire = 2417 rpm, still high but better (65 mph is 2245 rpm which isn't too bad)

Mitch, a 275 tire is as tall as I'd go. A 295 tire would be too tall IMO and not look right on the car. Too much big in the back and little in the front.

Lost in the 60s · President

Ah yes, I have 255's on the Camaro and they are short. You really should throw my 275's on and take it for a drive before commiting hundreds of dollars to a gear change. I can take them off the car and have them sitting here ready. It would take literally 10 minutes to have them on your car.

OK, just did some comparison sizing. A 295 is actually only 26.7" tall because it is a 50 series sidewall. Short and fat. A 255/70 tire is 29.1 tall !! It would be the same width as your current tread but even taller to help the ratio. The 29" tire may look to tall, as you said.

I have 235/60 on the front and the bias in size looks good to me but I like the rears to be wider/taller than the front for the "look". I would like to go to a 215/65 front to get the section/tread width .7" narrower and it would be 26" tall versus 26.1" for the 60 series. A 215/70 is 26.9" tall and would be a close match with a 275 rear.

-- Edited by Lost in the 60s on Saturday 5th of November 2011 06:47:48 AM

bwild70ss396 · Active Member

Sweet looking transmission swap! Overdrive is the only way to go. Would have put one in the El Camino if it did not have the original 400turbo