[RACER70]

Help
I would like some input on a camshaft
I have called crane and the fella was more than nice, I am not sure if I was satisfied with his recomendations.
I want a noticeable lump at idle, however I want all my vacum accessorys to work (power disc brakes) I want to use stock diameter valve springs and a stock converter
going into 66 ElCamino 350 cid Edelbrock intake (do not know model) Holly 650 w/vacum secondaries & headers Everything else is bone stock.
Thanks in advance for any input
Jeff Palazzolo
St Louis MO

 

[Doug Garland]

Go with a Comp Cams 270 or 280 Magnum.The 270 will be a little more streetable, and still hit a good little lick.The 270 will not cause any problems with the stock convertor, and the vacuum for the brakes, the 280 might create a few problems. Both cams will give you the idle you are looking for.

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

 

[drptop70ss]

I take it you just want the sound and arent concerned about how the engine runs, because either of these cams will give the noise but without the supporting higher compression the engine is going to be a stone. Need at least 9:1, if you are stock in the low 8s dont be suprised if the car is slower then it was. Also the 280 wont work well with a stock converter..the crane guy probably suggested a milder cam, which is right on the money with stock parts.

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

 

[68Malibu Blown 406]

For some extra lump without having to put in a pro stock like duration number, try selecting a camshaft in the 204 - 214 range @.050 with a lobe separation angle in the 110 or 112 range. The tight LSA will allow for some overlap at idle, causing the idle to be a bit rougher than the same cam with a 114 LSA. With the modest duration numbers listed, you will still have good low speed torque, and midrange will be excellent as well.

HTH

 

[Doug Garland]

Yeah, everyone wants the thump , but in your case ,without compression, and other factors, it's going to run terrible.The 270 Comp is the biggest you can run with stock convertor in their line.I would suggest a smaller cam , but you aren't going to get the sound you want.

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

 

[SSteve L]

Go with the cams these guys are suggesting and set the idle speed at about 500 rpms. That's as close as you are going to get to a nice choppy idle without drasticlly affecting your cars performance.
This reminds me of a good friend of mine who was in the right place at the right time when he bought his first car. He bought an early 70's challenger with a 440 that dyno'd 500 HP at the crank for I believe $1500-$2000 about 12 years ago. The car was a little rough, but had a decent paint job. Anyway, this thing was quick, one of the quickest cars around amongst the teenage crowd, but it idled smooth as glass at 900-1000 rpms, so he wound up always driving around with the idle at about 600 rpm just so it would sound tough at idle. This was the last car that needed to sound tough, because it was. He had plenty of power but it was his first car, and it wasn't right to him without the rough idle.


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Steve

72 Chevelle SS402/4sp

 

[RACER70]

Okay guys thanks for the input
What I should have included was fast is not what I am after Just something that has a little lump at idle and still be driveable
I think Steve L understands what I mean. Would still like more input
What makes the lump lobe seperation or duration?

 

[Doug Garland]

Both, to give you a short answer.A shorter lobe (110 and down) seperation will result in a rougher idle , when compared to the same cam with higher(112 up)lobe seperation. But most of the cams listed have around 110-112 LS.In order to change it, you will have to get a custom grind(read expensive).

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

 

[68Malibu Blown 406]

both duration and lobe sep make the idle rougher for the same reason, the overlap gets longer. If you put in a large duration cam with a wide LSA then it will idle rough and not have any torque because the intake valve closes too late on the compression stroke. If you put in a small cam with a tight LSA then the idle will be rough, but the mid range torque will stay about the same because the intake valve closes sooner and builds more cylinder pressure.

HTH