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-   -   Tech question-- (https://classracer.com/classforum/showthread.php?t=84465)

Greg Reimer 7376 03-25-2023 11:36 AM

Tech question--
 
If I took my '70 Monte Carlo and wanted to race it in Stock, would it be against the rule book to remove the front disc brakes on it and replace them with from drums from a Chevelle? I think the discs were standard equipment back then on the MC, but the Chevelle still had standard front drums until 1972.

David Lee 03-25-2023 03:02 PM

Re: Tech question--
 
Quote:

Originally Posted by Greg Reimer 7376 (Post 677931)
If I took my '70 Monte Carlo and wanted to race it in Stock, would it be against the rule book to remove the front disc brakes on it and replace them with from drums from a Chevelle? I think the discs were standard equipment back then on the MC, but the Chevelle still had standard front drums until 1972.


i would give tech a call, but i can not see a reason why you could not.

CMcAllister 03-25-2023 07:17 PM

Re: Tech question--
 
Rulebook says "Must be equipped with stock production four-wheel hydraulic
brake system, or aftermarket disc brakes"

Sounds like to the letter of the rule, if you remove the OE brakes, you must install aftermarket discs.

The next obvious question would be, why?

Catman 03-25-2023 07:46 PM

Re: Tech question--
 
Greg, I don't know your reason for wanting to switch your disc. to drums, but if it is to get rid of some weight be careful. Many years ago I had a 69 Chevy 2 with factory disc. on the front & was told I could get rid of 40 lbs. going to the drums. Had a friend with a Camaro with front drums, we made a trade I even did all of the work, well the only thing that I lost was time & alot of braking power. I weighed the parts as I was making the switch, the weight difference was nothing, but a deal is a deal & he was a happy camper. My car ran low 10's 130 mph. & it was hard to stop after that switch. Danny

Mark Yacavone 03-25-2023 08:41 PM

Re: Tech question--
 
Should be a bit lighter, from my experience..
Also ,less drag
Plus, it's easier to heat and bend the drum brake steering arms for toe-in issues.
Greg, Just do it..Nobody cares (except for maybe a few keyboard racers)

Greg Reimer 7376 03-25-2023 11:00 PM

Re: Tech question--
 
One thing about this whole deal, the discs were all power assist with the big round booster on the fitrwall. Drums either came power or manual. Running a vacuum booster with any kind of performance camshaft would absolutely not work,especially a Stock Eliminator type cam. That would be a weight saver as well.

Rory McNeil 03-26-2023 10:51 AM

Re: Tech question--
 
Prior to NHRA allowing lightweight, aftermarket disc brakes, many racers s swapped out the factory disc brakes for manual drums. As Mark said, less weight, and could be adjusted for zero drag. Funny, how, when many of the fast, higher classed cars, that had replaced the factory discs, for drums (and often to very light, small, 6 cylinder drum brakes), started lobbying for "Better" (read that as even lighter) aftermarket brakes, it became all about safety. Kinda like when lightweight racing seats were requested , again for "Safety". Have to wonder how many racers would have installed the aftermarket seats if they had to be the same weight as the seats being replaced, or heavier. I would guess "safety" would not have be as much of a concern in that case! As for the drum brakes, my buddys SS/F 66 Chevelle ran 9.7s at 138 MPH, on the stock 9 1/2" drum brakes, and another buddys 67 Mustang bracket car ran the same numbers with the original 10" drums. Neither had stopping issues, despite both being stick cars that went into neutral at the finish line, so no engine braking. Of course that also depends on the shut down length of the tracks being raced on. Cold drum brakes also often hold the car in the burnout box better than some manual disc brakes as well.

Randy Guest 03-26-2023 10:20 PM

Re: Tech question--
 
My dads 68 chevelle c/s 3680 pound car had drum brakes on it .at phoenix he could barely get it stopped at the turn off we had to put new shoes on it every race because they would get cracks in the pads on the shoe.go with disc brakes stock or after market. much safer .unstead of push and pray you stop.

killintime6968 03-26-2023 11:38 PM

Re: Tech question--
 
My ex-modified eliminator camaro has drum brakes up front. With times of high 9's to low 10's and speeds of 130s it was a bear to stop.

Run to Rund 03-27-2023 07:26 AM

Re: Tech question--
 
1 Attachment(s)
If you go from power to manual brakes, remember to include a retainer so the pushrod cannot fall out of the master cylinder cup.

Greg Reimer 7376 04-05-2023 10:40 AM

Re: Tech question--
 
Way back in about 1992 or so,I decided to build a '68 Chevelle with a 327 for Stock.I figured that if I didn't like the combo,I could always sell it off, so I found a rather ugly sun bleached metallic blue 68 Malibu in Lancaster, in the high desert, for $500.00. It had a perfect dent free body with no rust issues at all, a black interior, but it needed the whole rebuild, which it got. As I disassembled the car, I noticed that it had factory front disc brakes with two piece rotors that had the rotor removable from the hubs.The calipers, mounts and the spindles were exactly the same as the Monte Carlo, but it had a manual master cylinder that was wider than the drum brake master cylinder. I had never seen factory manual front discs on a Chevelle up to that time, or since then. Chuck Norton told me that early Camaros about that time had a disc option like that, so since he has early Camaros,I donated all that stuff to his cause and changed the car over to drums from some parts car I had that was a suitable organ donor. Never had a bit of trouble with the drum brakes, but since that combo in Stock rarely goes over 110 at the finish, it doesn't seem to be a problem. That was five Chevelles ago, the Monte Carlo now has the exact brakes the Chevelle has, and it seems to stop OK as well despite the weight difference. I seriously doubt that the car would have any consequential problems from the conversion.

FED 387 04-05-2023 01:52 PM

Re: Tech question--
 
In 1973 or so I decided to build a Modified Production class car--- I bought a bare bones 6 cylinder 3 speed on the column with no radio and a tinted windshield---cheapest camaro probably that Chevy ever built--less than 20000 miles little old lady traded it in on a new 1972 Nova 4 door cuz her lady friends couldn't get in the back seat--perfect interior and body just needed a good wax and buff Red with a Black interior ---Went on to put a 287 CI engine and a Nash 5 speed trans plus a Pontiac rear later tubbed the car and installed a full Moly roll cage ,swapped over for a 9 inch Ford rear with a 6:50 gear-- ran the STOCK factory DRUMS on the front and STOCK Ford 9inch DRUMS on the rear--as we progressed thru several classes finally settling on C/D/F MP and then F/MP only--- as a C car we ran speeds of 135-137 MPH never had any problems stopping but several Short shutdown area tracks would make you pay attention!!! Finally settled on F/MP and ran consistent 127 plus MPH----- so we decided to put Metallic brake shoes on the front wow you could almost "loc em up" if you jumped on them and got them hot !! but definitely helped in stopping!!!-----finally we put Semi-metallic brake shoes on the rear mostly to help with staging as the front Fully metallic shoes would not hold real well until they got hot---Never even/ever considered Discs at the time ---That car weighed as little as 2950 or as much as 3600 with driver---thats my experience ---FED 387

Coleydog 04-05-2023 06:47 PM

Re: Tech question--
 
Quote:

Originally Posted by CMcAllister (Post 677956)
Rulebook says "Must be equipped with stock production four-wheel hydraulic
brake system, or aftermarket disc brakes"

Sounds like to the letter of the rule, if you remove the OE brakes, you must install aftermarket discs.

The next obvious question would be, why?

Drums are “stock production four-wheel hydraulic break system”

Coleydog 04-05-2023 06:49 PM

Re: Tech question--
 
Quote:

Originally Posted by CMcAllister (Post 677956)
Rulebook says "Must be equipped with stock production four-wheel hydraulic
brake system, or aftermarket disc brakes"

Sounds like to the letter of the rule, if you remove the OE brakes, you must install aftermarket discs.

The next obvious question would be, why?

Drums are a “stock production four-wheel hydraulic break system”


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