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Cam selection help requested

2K views 4 replies 3 participants last post by  dave 
G
#1 ·
Lookling for slightly improved cam over stock for the 401 powered CJ7. I want to keep the stock torque converter (for a number of reasons) and was planning a cam w/ about 260 duration and .465" lift. This is about the characteristics of the Edelbrock performer/Crane Powermax 260-2/ Comp Cams 268H. What are your experiences with these cams?

I am looking for information in addition to the olf Feb and Dec postings on the subject.


My truck weights about 3600lbs, 3.73 gears, 30" tires, exhaust manifolds, 2.25" exhaust pipe, and generally drives in the 2000-3000 rpm range.
Thanks for the advice.
-Drew M.

 
#2 ·
I had a '76 Waggie w/AMC 401 that I used the Comp Cams 260H on. There was a bit of a rough idle. Bugged me all the time I had it. Wish I used the next step down, (252H?). I did some sand dragging and hill climbing with the rig, but 95 % of the time was below 3000 rpm. If I were to do it today, I'd probably choose something like the Crane PowerMax H-194/250 or maybe H-202/260. Too many people, myself included, overcam their engine for the application they really use it for. The Edelbrock Performer and Comp Cams Extreme 4x4 cams might fall in this same area.

Tim
'66 Jeepster Commando w/Buick 252/4.1L V-6
'70 Wagoneer w/Buick 350 V-8
 
G
#3 ·
I spent alot of time choosing the cam I put in my 360. I have not heard it idle as of yet. I fired it up for the first time last night an only heard it tear at 2000-2500 while breaking in the cam. I should have it idleing on monday, and then I will see how it goes. I used "Desktop Dyno" to get the general torque and hp trend of the cam I was getting. It is a cheap, but powerful program. The numbers it give are probably a little high, but the trend is good, which is important when choosing a cam to match an RPM range. Summit sells the program for about $40 I think. (www.summitracing.com).

I ended up choosing a wolverine blue racer cam (made by crane), It provdes a high torque band from under 2000 rpm, up to about 400 rpm, before it falls off at around 4500-5000. The dyno predicts 400 ft. lbs of torque at 1800 rpm. This is probably high, but at least I will have my max torque right off idle.

The specs are .448 int lift, .472 exhaust lift, 204 intake duration, 214 exhaust duration, 105 int centerline, an 110 lobe center angle.
This is very close to the edelbrock performer cam that summit sells.

If you got any other questions let me know

Jesse

Ignorance is the first step to knowledge.
 
#4 ·
Believe me you will be happier if you stay with something like the Edelbrock Performer...
Get a R'V., Towing, Torque cam...
If you stay somewhere around that level, you idle and drivability will be kept at acceptable levels.
If you get into those so called 'Horse Power' grinds, your Idle, low speed drivability, and low speed horse power will be affected, along with fuel milage going to hell...

I used an Edelbrock Performer Plus in the last Two 360 engines I did for customers.
Good vacuum, good idle, fair low end, really good mid range, good fuel milage...
You get the idea...

I'd recommend staying sensible...
BUT,
Opinions are like buttholes, everyone has one, and they all stink...
Take my opinion, and all other opinions, for what you paid for them...

Good luck, Aaron.

"I Have The Body Of A God... Buddha"
 
#5 ·
The AMC 401 will net some very impressive torque! The camshaft that would provide the highest level of torque (measured in foot lbs), for broadest RPM( 1500RPM - 4500RPM would the most usuable) band is what I think your goal is. There are several factors to consider in making good torque. One factor is camshaft lobe centerline. A close centerline of 106 or 107 degrees is favored for low RPM torque. A wide centerline of 110 or 112 degrees is favored for high RPM horsepower. Overlap is also a consideration for camshaft selection. Usually overlap of less than 60 degrees will have a good idle, while an overlap of 50 degrees will be baby butt smooth, and an overlap of 70 degrees will have a slight chop sound to it. Then there is lift to consider. The new Competition Cams Xtreme 4X4 profiles will open the valves very fast. For example an Edelbrock cam with the intake lift of .464 and a Competition Cam 4X4 Xtreme with a lift of .464 will open the intake valves at very different rates. Let's take the lift measurement at 95 degrees ATDC of the Edelbrock cam, .234". Let's take the lift measurement of the Competition Cam 4X4 Xtreme at 95 degrees ATDC, .294". Thats .060" more lift at the same angle time. The Competition Cam 4X4 Xtreme is working more like a roller camshaft profile. The net result of the faster rate of opening a valve will be a higher cylinder pressure of fuel air mixture. The higher cylinder pressure will build more torque thus producing more performance.

Let's not forget the other variables for camshaft selection, compression ratio, total gross vehicle weight, 2 barrel/4 barrel carburetor CFM and axle gear ratios will also effect the choice for a camshaft.
dave

 
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