Anyone here own or see a 70 C10 with factory disc brakes???

[68Gold/white]

Originally Posted by volksworld

i put the surburban disc brake crossmember in my 70 in about 1980 so i'm sure if he worked in a parts house in the late 80's there were already converted trucks running around....yes the 70 housing was wider and could use the later 5 lug axles....and a stolen 71 could have been re-titled ...4 pop rivits is a much easier conversion

This is just my opinion, thanks for your contribution.

Your 1980 disc brake conversion was not a common thing, back in the 80's The world was different back then. Mostly back then folks struggled to make a living. An old pickup was just that, an old pickup. They got repaired and used for what they were intended for, that was about it!!!

Prosperity among working folks with an old pickup they wanted to fix up was not too terribly common. The economy didn't really support doing the radical things we take for granted till around the late 90's (about when this website started).

My thoughts of ANY pickups in the 80's or most of the 90's converted to front disc would be an absolute minimum.
I'm sure quite a few conversions happened due to wreck repairs. A friend of mine's Dad had a nice 72. It got wrecked in the front. THe body shop located a cherry 69 front clip. They called him, asking if that would be OK. It was going to make repair price cheaper. I'm still trying to buy THAT pickup. It just sits.......

There's SOOOO many members here

[MARKDTN]

Originally Posted by 68Gold/white

.....Your 1980 disc brake conversion was not a common thing, back in the 80's...

I can't speak for trucks, but I did a bunch of disc brake conversions in GM A-bodies, B-bodies, and Camaros in the mid-80s for friends. It was a very common swap even then. Local junkyard was $60 for both spindles, rotors, calipers, rubber lines, and the proportioning valve.

In '93 I bought a front set from a '72 C10 to sell at a swap meet and it went pretty fast.

[67ChevyRedneck]

Having actually worked in an automotive factory, this is my opinion.

Disc brakes were a significant design change with new parts and a new installation process including the new 5 lug wheels and rear axles. The parts that were different were the brakes lines, hoses, master cylinder, brake pedal cover, tie rod ends, ball joints, spindles and associated brake parts (and I'm sure a few things I'm missing). This was not a simple change. Factory workers would have had to been taught how to install them, all the suppliers set up, etc. GM would have sent training trucks down the line when they were getting close to the switch. They also likely even shut the factory down for a week or two to retool for the change. When you think about it from a factory, parts, suppliers perspective, it just doesn't make sense. There would have been SO MANY more trucks with this "option" had it actually been an option than the very very few that have claimed they have it as an option (but have yet to provide any actual verification).

All research material I've ever seen points to disc brakes starting in 1971 as standard equipment, so for it to have been an "option" in 1970 there would have been an option code on the SPID and in all my years hanging around this place not one person that has claimed to have a 70 truck with "factory discs" has produced one single pic of a SPID with a J62 option code or any option code that references disc brakes. GM even had advertising for the 71 trucks with the "all new" disc brakes.

The only exception I can think of would be if a 1970 executive truck or test mule got out, but even those trucks wouldn't be a factory option, they would have been a factory conversion - a truck that would have been built off to the side or a separate shop with the new disc brake parts to test them out.

[special-K]

People have been playing with these trucks longer than some of you think. But, I remember people being fine with drum brakes till more recent years. Lots of mighty fine shortbed CSTs with 6-lug rallyes considered top-notch trucks. Not that that there weren't also disc swaps since not long after they came out.

[67ChevyRedneck]

I've been on a vintage mustang forum for quite a few years now because of my 65 and there's guys on there that have been playing with those cars since they were new and they claim people have been swapping drum cars to discs since they were new. I guess because of racing and handling? Discs were a factory option since the Mustang's came out, but that didn't stop people from using Granada spindles/brakes and parts from other cars for the conversions. Neat history is that they were made by Kelsey-Hayes. My 65 Mustang actually has Kelsey-Hayes factory disc brakes and it is listed on my build sheet.

[Coley]

Some very good points and perspective here so far.
In my opinion, I highly doubt that on the first January morning of 1971 the disc brakes trucks started to roll...so clearly they started back in the (early?/late?) fall of late 1970....which everyone seems to agree on.
That said, it would probably have been more likely to include/install an early grill on a disc brake truck and 'back badge' a 1971 and sell it as a '70 perhaps...than the other way around regarding the substantial changes to the disc brake system/undercarriage, noting that upper trim and badge stuff, and the spid was an easy change I'm sure....probably mostly administrative 15 minute stuff.
I'm just speculating here...but this would allow management to maybe change the 'production numbers' for the '70s vs. 71's if there was an accounting need or production numbers/quota issue, etc....again, simply by redoing some trim/badging/spid stuff....and calling it a 1970 still.
Who knows....GM was not exactly accurate or consistent with this production stuff back in those days....and by contrast we are splitting hairs here trying to find a pure unicorn etc, where I'm quite sure they would improvise any way they could to keep things moving.
my two bits.
Coley

[67ChevyRedneck]

Based on my modern experience, what would have likely happened was GM had the design complete, the testing/mules done, equipment and suppliers lined up, and they would have shut the plant down sometime around August/September 1970 to retool and organize the plant for the changes, again, this was a significant change. They would have likely reopened the plant after the tooling/process changes were made a couple weeks? later and started doing training with a reduced line speed on the new 1971 model trucks. Because this was a significant change, the chance of "left over" 1970 model grilles (and hoods, remember the 69/70 emblem was in the hood with holes for it!), etc being put on a "new" 1971 truck would be extremely rare in my opinion. *If* GM never shut the line down and made changes as the line continued to run (which I think would be extremely unlikely given the complexity of the change) is when you could end up with a mix of trucks/mistakes. But again, it would be a very limited small number of trucks with a high 1970 production number and not something that was offered as an "option."

A more likely explanation of a "1970" with disc brakes would be a 1971 truck (I'd assume a correct 1971 front clip) that was built from September - December 1970 that had VIN stamping error (unlikely, but has shown up here) or what was much more likely was a title/year error by the DMV assuming the "new " 1971 truck was still a 1970 model being it was registered in 1970 still.

[streetstar]

Originally Posted by GASoline71

Oh yeah? I have a 4 bolt main 327... so there!



Gary

Large journal mains too ?

[Coley]

Originally Posted by streetstar

Large journal mains too ?

.,...believe it or not I heard that the 327 engine blocks that were used for Chris craft marine engines back in the mid-late 60's were 4 bolt mains.

....now, I just heard this a while back from some vintage boat guys....so who knows?

Part of it, in theory....makes sense because the marine stuff is generally heavier duty than the automotive stuff (ie: forged cranks, etc, etc).....but I don't know.

...I'm not making any claims, but I do know those marine inboard (not I/O drive) v-8's were weird engines with timing dampers on opposite ends vs. the flywheel, weird intakes, waterpumps, distributors, starters, carbs, etc, etc...they definitely were not a stock motor as we would know them...confusing as heck to look at and solve when installed.
(imagine having the flywheel on the front of the engine...lol, some weird arrangements)

All good
Coley

[MARKDTN]

Originally Posted by Coley

.,...believe it or not I heard that the 327 engine blocks that were used for Chris craft marine engines back in the mid-late 60's were 4 bolt mains....

Not to jack this thread, but there is no such thing as a factory 327 4-bolt. See post #13 of http://67-72chevytrucks.com/vboard/s...d.php?t=688266

They can be made from standard parts, but GM never did it.

[demian5]

Originally Posted by franken

Even now, 2018 models are introduced in 2017 as 2018 vehicles.
Post #2, yay

And the 2017 are drum brakes

[Coley]

Originally Posted by MARKDTN

Not to jack this thread, but there is no such thing as a factory 327 4-bolt. See post #13 of http://67-72chevytrucks.com/vboard/s...d.php?t=688266

They can be made from standard parts, but GM never did it.

My sentiments as well.

However, it is possible that Chris Craft engine group might have done it with respect to marine engines?....who knows.....I don't, but it certainly was never any part of a GM car to my understanding.

All Good
Coley

[MARKDTN]

Originally Posted by Coley

My sentiments as well.

However, it is possible that Chris Craft engine group might have done it with respect to marine engines?....who knows.....I don't, but it certainly was never any part of a GM car to my understanding.

All Good
Coley

I don't believe so. 1 thing is certain, you cannot make a 4-bolt small journal block. There is not enough meat in a GM SJ block to make it happen. Therefore '67 back is out(except for '67 350 Camaro or Z28 which is large journal). So it would have to be a '68 up large journal block. There are no LJ 4-bolt blocks in '68 model year. So it could only be a '69 or '70. By that time the 350 was out and everybody was gravitating to it-from what I am seeing including Chris Craft. I have never seen any evidence of a factory 327 4-bolt in any application-marine, combine, over the counter, etc. People built them, but GM never did. All of these engines for outside are still built by GM engine plants so they can't have components that didn't exist at that time. They were just marineized or agriculturized by other companies like Mercury Marine or Pleasurecraft Marine for boats or Massey Ferguson or whoever with special exhaust manifolds or accessories.

[68Gold/white]

Thanks All, for your perspectives!!!

Some of the things I've thought about, some not.

Mark,
A friend told me he helped a friend, back in the day tear down the 327 in his 64 Impala, said it was 4 bolt main, I told him no such thing......that wasn't a good thing for me to say at that time, from a friendship point of view...man...

What WAS the last year for a 327? I'm thinking the 327 was carried into the 69 year model??? And was likely a large journal engine???, which could have had 4 bolt mains...Gary what year is yours???

I do remember 65 Mustangs as the first year for a mustang having front disc brakes, thought that was a good thing.

GM seemed to keep design changes to start at the beginning of a new model year. Ford had some 1/2 year stuff here and there, or they would use a part to a certain VIN or production date, that was hard to sell a part for.........

It would make sense that 70's had wide and narrow rear ends, getting ready for 71 discs, but kinda throws a fly in the ointment, if the made 70's with all drums and a wide rear end. The front and rear widths being same must have been purposely overlooked for those with drum brakes.
It would make sense to shut down the factory for next year changes, and maybe building a few 70's with 71 disc brakes. So they called "Those" 70 disc optioned pickups, whooppee.
Maybe the guy I had as a customer with a 70 disc equipped pickup had one of those tail end production units, maybe it was repaired with a 71 or 72 frame. Who knows.......

[lolife99]

Originally Posted by 68Gold/white

It would make sense that 70's had wide and narrow rear ends, getting ready for 71 discs, but kinda throws a fly in the ointment, if the made 70's with all drums and a wide rear end. The front and rear widths being same must have been purposely overlooked for those with drum brakes.

If I read this correctly,... you think the front and rear track widths are the same on these trucks.
They are not.
The front track width has always been wider than the rear track width.
Drum/drum brake trucks AND disc/drum trucks.
Doesn't matter which rearend was in it.
It's EVEN MORE noticeable on the 67-69 trucks (with the narrow rear housing), that people have added disc brakes to.

[67ChevyRedneck]

Originally Posted by lolife99

If I read this correctly,... you think the front and rear track widths are the same on these trucks.
They are not.
The front track width has always been wider than the rear track width.
Drum/drum brake trucks AND disc/drum trucks.
Doesn't matter which rearend was in it.
It's EVEN MORE noticeable on the 67-69 trucks (with the narrow rear housing), that people have added disc brakes to.

And GM hasn't stopped. I believe it's been done all the way up to the current model year trucks. When the "new" 2007's came out I remember a video showing a 4wd in mud and how the different track widths help the truck go through the mud better. Pretty sure it was one of the GM videos with Howie Long in it.

[Steeveedee]

Originally Posted by 68Gold/white

Thanks All, for your perspectives!!!

Some of the things I've thought about, some not.

Mark,
A friend told me he helped a friend, back in the day tear down the 327 in his 64 Impala, said it was 4 bolt main, I told him no such thing......that wasn't a good thing for me to say at that time, from a friendship point of view...man...

What WAS the last year for a 327? I'm thinking the 327 was carried into the 69 year model??? And was likely a large journal engine???, which could have had 4 bolt mains...Gary what year is yours???

I do remember 65 Mustangs as the first year for a mustang having front disc brakes, thought that was a good thing.

GM seemed to keep design changes to start at the beginning of a new model year. Ford had some 1/2 year stuff here and there, or they would use a part to a certain VIN or production date, that was hard to sell a part for.........

It would make sense that 70's had wide and narrow rear ends, getting ready for 71 discs, but kinda throws a fly in the ointment, if the made 70's with all drums and a wide rear end. The front and rear widths being same must have been purposely overlooked for those with drum brakes.
It would make sense to shut down the factory for next year changes, and maybe building a few 70's with 71 disc brakes. So they called "Those" 70 disc optioned pickups, whooppee.
Maybe the guy I had as a customer with a 70 disc equipped pickup had one of those tail end production units, maybe it was repaired with a 71 or 72 frame. Who knows.......

The 327 was still available in '69. I had one in my '69 Camaro.

IIRC, the 327 was still available in '70 in Canada, possibly '71. Any Canadians remember for sure?

[68Gold/white]

Originally Posted by lolife99

If I read this correctly,... you think the front and rear track widths are the same on these trucks.
They are not.
The front track width has always been wider than the rear track width.
Drum/drum brake trucks AND disc/drum trucks.
Doesn't matter which rearend was in it.
It's EVEN MORE noticeable on the 67-69 trucks (with the narrow rear housing), that people have added disc brakes to.

Coley made a post in another thread I started, theorizing about the front and rear end widths changing to match each other. I've never measured a Chevrolet, but CAN tell that classic Ford rear ends ARE narrower, AND NOT even centered with the front end. Built ford tough...LMAO...