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1970 Monte with Radical Camshaft.


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Hi, I have a 1970 Monte Carlo with a rebuilt 350 bored .030 over with a more radical camshaft. It also has a 700R4 Transmission. It runs great and idles ok when it's not in gear, but when put in gear the idle speed drops and sometimes will stall. Is there anything I can do besides increasing the idle speed. Any input would be greatly appreciated.

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  • jft69z changed the title to 1970 Monte with Radical Camshaft.

I have the cam specs. I don't know what the torque converter it has. I bought this car from Iowa. Hired the Lemon Squad to inspect it and they never road tested it, but lied on the report. I'm lucky the car never had any rust the paint is excellent and the engine was rebuilt. Transmission is good. I just had to deal with no brakes.

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I love the color combination. Great looking car. But( there’s always a but) IMO it’s missing some zip without the chrome. You may not be a chrome person and that’s ok, it’s your car, make it what you want. 

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Definite on the anodized trim on the bottom side of your Monte.That will make the paint "POP". As for the cam,  video would be great to here it. Sounds like it my need a vacuum canister since you said your brakes were having trouble too. Do you know how much vacuum you have at idle? that's why I have the canister,gives a little bit more volume with power brakes. Mine is not radical, Comp Cams 290deg. duration with .507/.510 lift. I also have a 2200 stall converter with the 2004r overdrive transmission with 3:42 axle ratio,29" 275/60/15 tires.post-259-0-93319100-1480263543_thumb.jpg I'm trying to set up a video of mine...... fingers crossed.

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So, what are the specs? By you saying that you're having brake issues , at the moment, tells me the cam is too big for the application. 

Higher stall converter and vacuum can or pump most likely are needed OR smaller, more combo, that you already have  friendly.

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Yes the camshaft was robbing too much vacuum for the power brake booster. When I got it the power brake booster and the master cylinder were shot, along with booth rear wheel cylinders. Front calipers were good. Replaced all bad components. Bled the brakes. Then I put in the best rotary vane vacuum pump, machined my own mounting plate. It's wired to the ignition. so that is what runs my brakes. It brakes great just like it would with a stock cam. As for the torque convertor I have no idea what it is or what it should have. As for the chrome trim, I guess the guy before me must have wanted a sleeper look. It even had rear fender skirts which I took off and sold. All the studs for the chrome are gone as are the openings for side marker lights. Those are the only place a plate was welded in, otherwise no rust or bondo anywhere. For the idle I just advanced the timing just a little and leaned out the idle mixture screws. I didn't want to increase the idle speed more. Now it will stay idling in gear. If anyone can tell me how to determine what torque convertor to use that would be great. I have access to a friends lift when ever I want.  Thanks Wayne.

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Wayne...... Cam specs! What are they? 

Glad the brakes are working like they are supposed to. 

We need the cam specs to determine what torque converter recommendations to make. 

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7 hours ago, 420ponies said:

Definite on the anodized trim on the bottom side of your Monte.That will make the paint "POP". As for the cam,  video would be great to here it. Sounds like it my need a vacuum canister since you said your brakes were having trouble too. Do you know how much vacuum you have at idle? that's why I have the canister,gives a little bit more volume with power brakes. Mine is not radical, Comp Cams 290deg. duration with .507/.510 lift. I also have a 2200 stall converter with the 2004r overdrive transmission with 3:42 axle ratio,29" 275/60/15 tires.post-259-0-93319100-1480263543_thumb.jpg I'm trying to set up a video of mine...... fingers crossed.

Man, that sounds good!

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Ok here are my cam specs:  Edelbrock #7102.  Lift at cam Intake .325"   Exhaust .340"     Lift at valve Intake .488"   Exhaust .510"   Timing at .050 Lift Intake 10^BTDC  Close 44^ABDC     Exhaust Open 59^ BBDC  Close 5^ ATDC.  I am not used to what all this means.

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Lol it's ok. I still don't fully understand all of it either, but if your converter is stock stall speed, buy the sounds of it it is, you need at least a 2500 stall speed converter for it to idle and have good manors. 

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Thanks for all of your input. Do you think a 2500 stall convertor is enough. where would you recommend getting one. I don't really know the definition of the stall speed. I'll have to wait till spring to get one. I have put $2000 worth of parts in it this year just to get it running good. I will be on vacation this week, so I won't be able to reply until Saturday. Thanks again  Wayne.

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It would be great for you to become a member. Best $25 you'll ever spend. I'll get some info from the guy who's built my Turbo 400 in / near your area.  Need to know what transmission is in your car, rear axle ratio/ size tire( inches tall) that way you can get correct speedo gear( bet it's off). I'd say 2200-2400 stall. Mine(2004r in now), has a switch to leave it out of o.d. if needed.

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Thanks Sammy, it's a old school build. Vic Edlebrock built one like this back in the early '90's in HotRod Magazine. I did about the same except the heads were angle milled to get me 67cc chambers. That's how it makes 10:2 compression. 420 hp,hence my avatar name? I'm a gearhead from Jacksonville, N.C. Built motors at Alan's High Performance back in the 80's. Nothing like having 4 drag strips in a 50 mile radius. We built a '71 Monte pro street with a 427 BBC there ,White  with fading pro stock stripes, Keystone Klassics on it, you might had seen it around.

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My car has a 700r4 transmission. When the engine is at operating temperature from park or neutral it drops into gear hard. Then it shifts from 1st to 2nd at 15 - 20 mph, and it chirps the tires, it has that much power. It has 12 bolt posi. I'm still on vacation. So when I get back home I'll let you know what I think the gear ratio in the differential is. Just knowing this, does it seem like l need a higher stall torque converter. That Lemmon Squad didn't road test it. I wish I had a stock camshaft. I'll give you guys my rear gear ratio when I get home. Thanks again for any information.   Wayne 

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Quick question..... What carb are you using..... 

When I first got mine, she had been set up for lower elevations, so i had to hold the gas pedal just to keep her running. I wound up backing up the air screws and leaning out the jetting.

As for the transmission, when I put a rebuilt 200r4 in, it took several attempts to set the TV cable.... Finally took it to the guy who did the transmission to get it right.

Also, did you have your 700r4 rebuilt ? If so, they probably upgraded the springs and clutches, which will put a bit more "snap" in your shifting. 

How this helps. :)

Scott.

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Edelbrock carburetor 750 cfm. Yes I had a good mechanic adjust the springs and other things in the valve body. He said he got it as streetable as possible. 

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My 72 has a mild roller cam and lifters with a 700r4 and 3:73 posi in a 8.2 10 bolt if I get on it slightly it will chirp the tires easily. I am getting around 14 to 16 MPG since I put on the Holley Sniper EFI which is better than the Eldebrock 1406 was getting at 12 MPG

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I get 12 mpg city and 18 mpg hwy. At 65 mph tachometer is at 2000 rpm. When I get home and figure out my rear differencle  maybe someone can help me figure out a stall converter.   Wayne 

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Sounds like you're running 2.73 to 3.08 gears in the differential, assuming your in overdrive at 2000 rpm. That might have a small effect on your take off.

A stall converter around 2300-2500 rpm seems to work in most cases...... 

Is your 700r4 equipped with a "lock up" converter ? And, if so, did they wire it up correctly ?

Just a note, gear ratios are stamped on the ring as a ratio...... last 4 digits, (13-43= 3.31... ) etc. Montelishi7.thumb.jpg.e34738561982193c749e7d44ce1a0667.jpg

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3 hours ago, Scott S. said:

Sounds like you're running 2.73 to 3.08 gears in the differential, assuming your in overdrive at 2000 rpm. That might have a small effect on your take off.

A stall converter around 2300-2500 rpm seems to work in most cases...... 

Is your 700r4 equipped with a "lock up" converter ? And, if so, did they wire it up correctly ?

Just a note, gear ratios are stamped on the ring as a ratio...... last 4 digits, (13-43= 3.31... ) etc. Montelishi7.thumb.jpg.e34738561982193c749e7d44ce1a0667.jpg

 

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