Tech question--

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

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

Quote:

Originally Posted by Greg Reimer 7376

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

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

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

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

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

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

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

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

If you go from power to manual brakes, remember to include a retainer so the pushrod cannot fall out of the master cylinder cup.

03-25-2023, 11:36 AM	#1
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,135 Likes: 172 Liked 705 Times in 219 Posts	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.

03-25-2023, 07:17 PM	#3
CMcAllister Senior Member Join Date: Sep 2006 Location: Fulton County, PA Posts: 614 Likes: 16 Liked 920 Times in 259 Posts	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?

03-25-2023, 07:46 PM	#4
Catman Junior Member Join Date: Feb 2019 Location: Martinsburg, WV. Posts: 9 Likes: 1 Liked 2 Times in 2 Posts	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

03-25-2023, 08:41 PM	#5
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,815 Likes: 2,903 Liked 5,120 Times in 1,951 Posts	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) __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

03-25-2023, 11:00 PM	#6
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,135 Likes: 172 Liked 705 Times in 219 Posts	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.

03-26-2023, 10:51 AM	#7
Rory McNeil VIP Member Join Date: Jun 2007 Location: from Vancouver BC Canada, now in Nova Scotia Posts: 1,311 Likes: 317 Liked 1,103 Times in 301 Posts	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. __________________ NHRA 6390 STK M/S 85 Mustang

03-26-2023, 10:20 PM	#8
Randy Guest Junior Member Join Date: Oct 2013 Posts: 52 Likes: 2 Liked 27 Times in 14 Posts	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.

03-26-2023, 11:38 PM	#9
killintime6968 Member Join Date: Oct 2009 Location: Whitecourt,Alberta,Canada Posts: 236 Likes: 4,633 Liked 91 Times in 29 Posts	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. __________________ Bruce Cameron 68 Nova 396 E/S 68 Camaro SS/? ex Checkmate Modified

03-27-2023, 07:26 AM	#10
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: Tech question-- If you go from power to manual brakes, remember to include a retainer so the pushrod cannot fall out of the master cylinder cup. Attached Images