To cam, or not to cam...

Michael Yount said:

Be careful on generalizing about the cams Kevin - how they behave is dependent on a bunch of variables - the rest of the engine components, static CR, displacement, etc. A cam that lopes hard in a 302 with 9:1 CR will be MUCH milder in a 10:1 347.

My custom was designed with my set up in mind - and I'm constrained on the exhaust side (2.25 head pipes into a single 3" system).

The cam has very little lope - sounds a little more agressive than stock; 18-20" of vacuum at idle. The car will pull without hesitation or bucking from as low as 1100-1200 rpm in 4th or 5th gear. And it gets 18-19 mpg around town, 24-26 mpg on the road. It makes no less than 270 lb-ft (crank) from 1700 rpm all the way to 5000. VERY flat, broad torque curve. Peak torque at 3800 rpm (about 335), peak power at 4800 rpm (about 275). I'm very pleased with it.

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You are correct as usual. I need to be careful when generalizing. Just wondering what your opinions were.

I was thinking on the lines of a rebuilt 306 around 10:1 with AFR 165's along with my current intake and mass air.
I am not interested in peak HP but more interested in a flat torque curve with good low to mid range torque, good vacuum, good all around drivability, that will make better numbers then a stock cam with very mild characteristics.
Like you said earlier "Best of both worlds"
I am not looking to run a lot of RPM, 5500 or less. Pref. 5200.

I would be happy to duplicate these results with the torque curve, but if I can go even better than this then I would be even happier.

I would like the cake and eat it too.

We should keep in mind that the cam that Michael Y uses with alum. GT40 heads, and that AFR said would work well with thier heads, is not likely a cam that is going to work well with ported E7's.
The cam Buddy Rawls ground me is based on a ported E7 head. A while back I was contemplating going back to totally stock E7's, Buddy said the cam would work well in that situation(not optimal) but what ever I do, don't thro aftermarket alum. heads at the cam, as it'd be all wrong.
I 'assume' the opposite would apply.

90mustangGT said:

All a cam is going to do to a stock engine is shift the powerband where the engine really can't breathe, making it slower even thought there would be a gain, the average TQ across the powerband would be lower ~ making it slower even thought there would be a gain, the average TQ across the powerband would be lower. A cam on a stock 5.0, maby a really mild one for gains, yes, but a very mild one.

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Unfortunatly, most folks have no idea how to select a cam and as a result the above is the norm.
However, selecting a proper cam for the application will make more power, depending on where you want it.
To say a cam on a stocker will move the power band out of reach is not real, Ed Hohenberg runs NHRA stock, 11.9's and shifts 5600-5200rpm depending on gear being shifted. This is stock territory. But the cam was selected properly.
290rwhp and 330rwtq and 11.9's n/a with stock shortblock, untouched heads/intakes in my opinion is no mild gain.
Now, would you want to drive this car daily, likely not, but the performance certianly shows that gains are to be had on a 'stock' setup.

90mustangGT said:

Try to stay in the mid .400's in lift because the heads don't flow any more after 4.50 and the stock valve springs can't take it. Stay in the teens in durration. Such as a 212-216 on intak and 214-220 in exaust durration.

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Any cam worth a look at is going to require upgraded springs.
Has less to do with lift/coil bind than it does ramp rates and bouncing valves.
A ported stock head should flow max at over 0.500, mine flow max at 0.600(only by a couple of cfm mind you). Given that. you'll likely want something that has lift in the mid 0.500's.
If 95% of the heads max flow is at 0.500... why have a cam that only goes to 0.500? If having the cam lift to 0.530-0.550 would allow a more aggressive ramp with a longer transition at the top, hanging the valve open longer where it flows the most, and going by 0.500 twice in one revolution, rather than once.
Also, a 'stock' head does not need a split durration cam.
I've seen specs on a few custom cams for stock, and ported stock heads, and none of them have had exhaust biased lift or duration specs.

So,
Fett,
Running the stock cam will have gas mileage and 500rpm-2000rpm advantages over a typical off the shelf unit.
I would definatly not run the E cam with ported stockers. The E was not designed for 'stock' applications.
My custom cam designed for ported stockers has identical lift/duration specs, in excess of 0.540 and 220... something to think about.
Seems when dealing with a restricted combo, there is inevidably(sp?) going to be trade-offs.
If you want gas mileage and off idle response, likely the stock cam is as good as it's gonna get, if you want to make a bowl of power, then something has got to give.
So...
you wanna make a litte power and give up some 500rpm-1200rpm drivability, cam it... you wanna really make some power, and give up mileage and charateeristics under 2000rpm, cam it... you wanna have a combo that makes your wife happy on her commute to the hair salon, don't cam it.

Good Luck.

I think what we're all pointing at here is that there are only a handful of folks out there capable of modeling these things so we take the guesswork out of it. Let them do the cam design. Kevin - for the money you're investing in the rest of the motor - well, the CompCam is gonna cost you at least $200, probably more like $250-300. For somewhere between $25 and $75 more, you can have Buddy or Ed make you a custom that fulfills your wishes to have your cake and eat it too - just what I did. With $2-4K in the motor - why would you not spend another $50 for a custom? Even for the "E" crowd - with that kind of money in a motor, why guess at a cam?

Having given my free advertising to Buddy and Ed, I'll add this. One of the things I've paid attention to over the years is the flow ratio on the heads. The AFR's have about an 80% peak exh/int flow ratio. Stock E7's and Y's are down in the 71-72% range. It seems like the lower you want your peak torque and power, the more you need the cam duration and/or lift to help the exhaust side --- split pattern cams. So, I have no doubt that an X258 would produce the kind of characteristics you're talking about, but I'd bet with AFR's the custom you get out of Buddy is gonna look less like a split pattern, and have more even duration between intake and exhaust. Why not give him a shot at seeing what he comes up with?

By the way, when I get my 'real' exhaust on (full 2.5" w/Xpipe), the Y head will still want a little help on the duration side according to Buddy - but not as much as the CompCamXE line have.

I actually never set out in the beginning to have any specific goals with the stock cam. I basically had planned to run the car this past season with the top end done like it is, then actually rebuild over the winter and then put a cam in. Something custom for what all is on my car. But in all honesty, I got lucky and its running so well, I dont wanna touch anything. I took the car to Chicago this past summer and from Leamington Ontario to Bolingbrook IL, it used a hair over 3/4s of a tank w/ 3.73s and 5 speed. It was about 6 hours drive, and I did around 70-75 MPH all the way.. [the higher 5th gear in the T5-Z helped here] Idled at the border for probably a half hour in hot weather no probs...

It's funny because at the track, even when I have the revs at 4500 staging the car is dead quiet, then when I dump it and go WOT people jump because it gets so loud so suddenly, the slicks make some noise and it takes off.

I'm just going to concentrate on hooking hard with a new posi unit, maybe 4.10s, and do little things like the 70 mm TB, and eventually a manual rack.. I have yet to try a shortbelt too.. so that should help. Of course it would make more HP with a properly ground cam but after seeing how decent the stock one is working out, I dont think I am willing do give up the dead smooth idle and stock like driveability for it. If I ever feel the need to go midish 11s i'll put a 55 or 75 HP dry shot on.

Michael Yount said:

Kevin - for the money you're investing in the rest of the motor - well, the CompCam is gonna cost you at least $200, probably more like $250-300. For somewhere between $25 and $75 more, you can have Buddy or Ed make you a custom that fulfills your wishes to have your cake and eat it too - just what I did.

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Thanks Mike. I don't mind paying a little more as long as I get what I want. Like I said before I was happy with these results if I could duplicate them. So if they can give me a little more then I will do it.

I will give Buddy or ED a call when I am ready.

Thanks again.