I was wondering if you have any suggestions on a good cam for a real lopey idle for a 79 302 I have heard from a couple of people that I should use an rv cam is this a good idea.

 

[updated:LAST EDITED ON 28-Jul-02 AT 05:34 PM (EST)]The problem with lopey cams is that you lose a lot driveability witht them, like idle, and you'll have to make sure and keep lift below .50" because the stock springs will not work right, creating valve float.
Anyway, rule of thumb is that the more duration, the more lope. Duration @.05 should be around .224* for a good lope, something similar to FRPP's "B" cam for roller motors.
On the other hand, for a stock engine why worry about a cam? Your motor just won't gain much from it, at least not as much as it could possibly lose. Running a "B" cam on a stock engine will lose a lot of low-end performance and only gain mildly up top because the stock heads won't build power to the cam's potential.
Just something to think about.

 

well what type springs do I need to get for my head I don't plan on pulling anything so I am not terribly in need of low end torque I want the lope through a set of headers and flowmasters I plan on using a edelbrock 600 cfm carb don't exactly know what intake yet.

 

I'm probably not the best person to ask about lope as I'm much more into building engines for performance, not sound. What you're looking for is sound at the cost of performance.
When you look at "truck" cams, they have durations of 204/216* @.05", which builds low end torque and mid-range power, right where trucks like it.
Like I said, the spring rates for stock springs won't take lift above .5" lift. If the heads have lots of miles on them, pull the heads and have higher rate springs installed, any engine shop can do that.
That carb will be perfect for the lil' 302, and you may want to go with the matching Edelbrock Performer intake if you don't want to use the stock one. The Performer builds power from idle-5000 rpm, where trucks make power.
Back to cams, take a look at the Crane PowerMax cams, part #'s CRN-443942 and CRN-444552. The former has durations of 216/228*, the latter at 222/234*. If you go with the first cam, you'll probably be able to use stock springs, but you'll lose some power at the top of the power band due to valve float. If you use the second cam, well, you'll need new springs. You'll also lose lots of power down low and your engine won't be able to meet the demands of the camshaft because the heads simply can't flow enough air for the cam up top.
Anyway, check out Wolverine and Lunati as well as call around to CamMotion and others lookin' for a custom grind cam.
Finally, think again about whether you want to drop this cam in your engine. I was told once that in building engines, if you're keeping it rather anemic and stock in performance, buy the sticker from your favorite cam company and put it on your car and keep the stock cam. Cams should be bought to allow the really cool heads you buy to perform at their highest flow potential.
Just a thought.
Later,
Ben

 

I had an Isky flat tappet hydraulic cam in a 289 that sounded awesome - had a choppy idle but would still idle at about 650 - 700 RPM in gear with an automatic (stock converter). It had good low end torque, and would rev to 5500 RPM +. I read in a magazine once that this was the best street/strip cam out of the ones that were tested - that was before roller cams. It had 270 duration, and .496" lift. You will need some heavy duty springs though - unless you don't mind the valves floating at high RPM. Now days with the roller cams out there - you can have the same performance without the choppy idle (although the choppy idle does sound cool).

 

If you want to go fast, then you can't just throw away your torque, you're not driving a 2800 lb trailor queen Mustang. Go with a cam in the 210-212 intake duration seat to seat, and you'll go much faster than a cam that doesn't make peak torque until 4500 RPM. The fastest cam that I've seen is Comp's XE 256 H, an Xtreme Energy grind that perfroms from 1000-5800 RPM. Your motor does not need to spin harder than that, you're just making noise and wasting gas. I have the XE 250 H, it goes (210/218) @ .050" lift, with the max lift being .463/.477" int/exh, and it kicks like an FE off the line. Whatever you do, a dual-pattern cam is the Torque champion. Dual pattern means different durations for the intake and exhaust valve. You're going to have to change your valve springs for any major power-building cams, and stock heads will never make use of the extra power that the cam generates. For a non-7000 RPM motor, a dual plane manifold is the way to go, but if you use it with a long duration camshaft, then you're negating the low-end grunt of it, and the motor will run poorly. The key to a powerful engine is well-matched components, like a <212 duration cam, big valve, small runner heads, and a dual-plane intake. For lighter vehicles, a large cam with big-valve large runner heads and a single plane will run very well at high RPM and be very fast. Just remember that all the components you bolt on need to compliment each other, or your engine won't run well at all. TK

'77 F100, 302 (the aftermarket Prodigy), C4
Cadet Second Lieutenant John F. Daly III
South Carolina Corps of Cadets, The Citadel
The TorqueKing

 

you're not driving a 2800 lb trailor queen Mustang.

Ouch, that hurts.
Of course, that's why I was suggesting that the max duration that he use be around 224*, and also why I suggested that he not mess with a cam at all until he's ready to build the entire motor.
In other words, I agree almost completely with TK on what he said. Again, that's why I suggested the Performer intake. You're building a motor for a truck, not for a trailer queen Mustang.
So, like I said a few posts ago, really think about how you want this truck to behave, and decide whether or not you want to sacrifice the drivability and performance of your truck for a minor gain in high end performance that you'll probably never see and a drop of low-end torque.
Good luck, and thanks TK.
Ben

 

well thats kinda what I am going to do I am gettting an engine built to go in my truck and all I want is a little lope is that so much to ask for.

 

Don't mean to **** you off but I wanted to relate this story.

Years again I had a friend that wanted me to help him build his motor. All he wanted was for it to be start hard, sound good and lope at idle.
This is the only infomation I could get out of him.
So I went told him the engine specs.
Pull a spark plug wire, drill a small hole in the exhaust just behind the exhaust maniford and advance the timing.
Boy was he pissed off!
Everyone else thought it was the perfect answer.

 

Before you go and waist money and performance look at your exhaust.
I have a stock 302 with glasspacks and has a small but noticable lope at idle. If that is all your after change your exhaust to a loud one with a lower idle.

 

The Comp High Energy cams 280 and larger will lope a little, and they won't be too abnoxious, as long as you have plenty of gear (3.70's or numerically higher). That Isky cam that Lightnstruck mentioned sounded alright too. The worst thing that you could do though is put a long duration cam in a motor with stiff gears, because then you won't go fast or get good milage, but you will sound cool at the stoplight. For a slightly noticable idle without a significant loss in drivability, go with something in the 280/280 duration (seat-to-seat), and have plenty of gear. Didn't mean to lecture earlier, but when you ask for a cam recommendation from anyone who knows what they're doing, you should list things like auto stall speed or manual, vehicle weight, and rear end gear ratio, as well as primary purpose of the vehicle. That way you don't get talked into buying a weekend bracket warrior cam that will barely get your '79 rolling from a gross lack of low end torque. TK

 

Most of the time the lopey idle will mess up your carb at the same time. In other words, it will be a beast that you will get tired of trying to get right. The lopey idle causes very low manifold vacuum at idle, which makes the power system in the carb come on(whether it's a power valve, or needles in a edelbrock) which dumps too much fuel in the engine and makes it run rich.

 

Sorry I got aggrivated with you guys I should have gave you more to work with thanks for the information.

 

Give lunati a call they could probably give you some guidance, my brother has one of their cams in a BB and he drives it as much as possible and through mufflers it sounds like a funny car and it has been two years since the rebuild and it runs fine, just a thought.

 

if anybody really wants to know how I want it to sound go to flowmastermuffers.com and click on the installation video for the chevelle and listen to the start of the video when it is idling no I'm not a chevy fan but that is the way I want my f100 to sound.