I decided I'd like to get a cam with higher performance than the stock one in my new 5.0 roller motor (bored .040, stock heads, air gap intake, new 600cfm carb but i can exchange that if necessary, headers). I called Summit and the sales rep got me all confused. He said that there is no way to pick a cam before I decide on a torque converter and what rear gears the car will have. Right now I have the stock converter and gears. Do I really have to decide if I'll get a higher stall speed converter before I pick a cam? I think I will ultimatly get 3.55 gears but not sure(now 2.79). Is there a cam that will yeild improved preformance with my stock setup? Or do I have to do like he was saying and change it all together to get good results? What cams do you reccomend? Confused...:confused: PS this car is for street use and I'm tring to keep cost down where it makes sence to. mabe I should not be looking at the cam at all and only at the conveter and gears...:confused: ...Help please
Well, the Tech Guys there are ... well tech guys. Obviously you CAN chose a cam prior to getting your other gear - it just won't work as a 'system' until everything else is matched up. Here's a link to some standard FRP cams and their intended max power band. http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=1329
That is a useful link, thanks. The E303 might be right but I'm also looking at comp cams 35-420-8 and 35-440-8 (http://www.compcams.com/Technical/CurrentCatalog/HTML/76-81.asp). I've discovered that I need to leard more about this subject before I can choose. What should i read to educate myself? Can someone please explain duration and lift and how cams affect RPM and idle.
The more I learnt, i see that I want to work with all of the following variables: 1. cam 2. torque converter 3. rear end gears The givens in the car right now are: 5.0 roller motor bored .040, stock mustang heads, air gap intake, new 600cfm carb (holley 4150) but i can exchange that if necessary, headers, and a c4. The intention for this car is a high preformance street car that souds mean, good power off the line but can comfortably cruise 65-70. I'de appreciate people's oppinions on filling in the specs. on the above 1. 2. 3. Thank you
Dan, I don't profess to know all about cams. I have to rely on the wild world web. Here's a pretty in-depth look at cams and how they effect a 'system'. http://www.car-forums.com/s9/t1318.html If you can tolerate the background on this guy's site, he goes into the cams a little in depth http://www.ahsdc.org/goblins/tech/cams.htm I'd go to www.google.com and enter your key search words. There's a overwhelming amount of information and opinions on cams or 'sticks' as they're also known by. Gluck, R
first you need to decide how you want to use the car and what you are willing to put up with as to streetability. the 600 holley is a great all-around carb and good on a 302 to over 6,000 rpm (closer to 7 in a pinch). in general, a cam around 218 -228 deg @ .050 with about .500 lift will give a power range to about 5500 rpm. probably start power around 2-2500 rpm. a converter stalling around 2300-2700 with a 3.55 to 3.70 gear on a 26 inch tall tire will give you a very peppy car with et in the 14 second range or better, but still be fairly streetable. you might not enjoy doing 70 mph on the interstate in it for any lenght of time. you have to decide what you want and what you will live with both while doing it over time and after you get there.
Dan, you ask in your first post if there was a cam that will improve the stock setup. There is but it won't be the best selection for future upgrades. First reason why you were told not to pick a cam until the driveline was changed is because the longer duration cams lose low rpm power in favor of increases in the upper ranges leaving you with a very soft bottom end until the rpm comes up into the new cam's power band. Lower gears and higher stall converter gets to this point very quick so this covers up the soft low end.
My mustang is about the same engine as you're building, with the exception of lightweight internals and ported D5AE 351w heads, whether that makes much difference. I run an Erson hyd. roller cam, 226-228 @ .050" lift 114 LSA and .512" lift on both. I also ran it with a turbo, and I am told by the techs that it "likes" N20 as well. The powerband is about 1500-5500, very wide and very torquey for a 302, though I'm able to squeeze a few more RPM out of it with some ignition and carb tuning (not giving away my secrets!!), along with the light internals. Also gets 30+ mpg with the 5 speed cruizing at 2000-2200 RPM on the freeways at 70 MPH. The only complaint I had with it was that it fell off quickly after 4500 with the turbo, but that was more because the compressor was going into surge and the headers weren't up to the task. It did, however, provide EXCELLENT power from 2000-redline, and still does on the 302 I have it in now. It ain't a rocket, but I figured running 8.20 in the 1/8 @ 88 mph and still getting 30+ mpg wasn't too shabby for a 3000 lb hatchback. I can't find the darned part number for it, but it's listed on the Mr Gasket website under camshafts. I tried to find it there, but apparently Linux doesn't like the webpage and it generates errors
My opinion is, and it's only opinion, that under ideal circumstances the gears and converter need to complement the camshaft (and the rest of the engine combination as well) rather than the other way around. If you do not plan to change the gears and converter than they really do need to know that information. Ideally, the camshaft needs to bring the heads, intake and engine size together within your desired rpm range. In response to your other post, I would do the following: 1) assuming unported heads and stock compression you are going to be limited to a camshaft with no more than low 22x degrees @ .050 on the intake and maybe mid to high 22x on the exhaust. You will need at least 110-112 degrees of lobe separation to keep the power band wide. Cams this small will liit your lift to less than .500 unless you use higher ratio rockers. It will have a noticeable idle. 2)You will need a converter much over 2200 rpm range. 3)3.55 with a 26" tall tire.
Dan, if you have the stock 5.0 HO cam then leave it in there.Take a look at the factory stock/pure stock mustangs,they run low 12's with this cam.Specs are 276/266, 210/210 at .050, and.444/.444 lift. Add a set of 1.7 rockers to increase the lift and you've got a great match for stock heads.Good performance AND good driveability, even with a stock converter and gears.Car Craft did an article a while ago with a stock 5.0, this cam,1.7 rockers,and a set of AFR 165 heads- made 400 horses.
Bluegrass, thanks for that explanation of the concept. now it makes sence to me. mavman, I like the wide powerband on the Erson cam. Being that it starts at 1500, should it be used with a stock converter? What rear end gears are you running? Timsm, your idea is interesting, I have to look into that. There is no cam installed yet and I can still go any cam How do larger tires vs. small ones come into play here? Mine are relatively small. Which part of the cam spec is responsible for the smooth vs throaty rumbley idle?
Choosing / Selecting a Converter Thought I'd add this link to this topic for search purposes. Things to consider when ordering a convertor (site does not allow hot-linking). (obviously every converter will not perform exactly the same on a different car) see specheet at http://www.lentechautomatics.com/specsheet.html
I agree with Tim, and to some extent the Tech Guys. I big cam isn't rewarding running those gears and converter. The 1.7 rockers is a good idea too. Tech guys can be just as misinformed as anybody else, but they are right about the package concept. If your are changing converter and gears real soon, you can get away with a bigger cam. If not, wait till later.
