Help me pick a cam!

[smercier]

Alright guys, it's finally time for my 289 to give way to a 5.0. With that being said, here are the players:

Holley 1850 / 600cfm
Weiand Stealth (8011) intake
Ported Gt-40 heads
1.6 roller rockers
stock CR 5.0 short block

The CR here will be ~9.0:1. I may shave the heads a little bit depending on the lift of the cam I choose, but I do want to avoid notching the pistons if I can).

This will be mated to a T-5 and a 3.00 rear. The rear is likely to change to something > 3.5 in the near future, as the rear is currently open and I can't stand it.

I've still yet to decide on headers, as I want to figure this out after I've completed the swap. The reason here is that I anticipate some header clearance issues with the clutch cable / other items and I don't want to have the car down for more than a few days.

The car will be driven daily and will rarely, if ever, see any track duty. Therefore, low end torque is a must, but I'd like for it to pull to 5.5-6k if need be. Something with a little lope at idle would be nice, but I don't want to sacrifice a ton of driveability.

Your thoughts and comments are certainly appreciated. Thanks in advance!

 

[302 coupe]

stock HO cam, or something mild like a B or E 303 cam.

 

[SoCalCruising]

The lift should be tailored to the flow of the heads. For example, if the heads don't flow over .500" valve lift, then using a cam with more than .500" lift is detrimental to power production because flow often deteriorates at lifts greater than the head's peak flow, and probably a little before peak. Try and find out what the flow numbers are/will be and pick a cam with lift that is 5-10% less than lift at peak flow of the intake port. Then check the ratio of intake flow to exhaust flow. That will determine the relationship between intake and exhaust duration. A ratio of around .75 and you can use a single pattern cam. I would use an LSA of 110-112 degrees. For torque in the low/medium RPM range, stick around 220 degrees duration. All this said, the E303 cam may be a good choice. Another benefit is that it won't require much valve spring. The E303 is dated, however and you may find similar grinds with better ramps. Anyway, that's my $.02 and a one-paragraph cam primer. Take it for what it's worth.

 

[fasttback]

Start looking at cam grinds with the following specs:

Hydraulic roller or Flat Tappet

Total lift between 0.470-0.512"

Duration (@ 0.05") between 205-220

Lobe separation between 110-112

 

[D.Hearne]

Go with an HO roller or an F4TE roller, either of which with 1.7 rockers. The F4TE will give you everything you want, just without a lope, mileage, power, pulls from idle to 6000 rpms. Also gives the compression a slight boost because of it's lack of overlap.

 

[57fairlane]

I just can't stay away from cam threads . . .

The FMS E-cam is indeed a good choice here. If you want a little better performer, speed pro (wolverine) makes a cam, the 1190, that is 212/222 @ .050 with right around .500 lift on a 112. If cost is a big concern, the idea with a stocker roller and 1.7s is pretty good. You can usually pick up a stocker for next to nothing as the next most expensive is an E with right around 80-100 used or 150 new and then the 1190 speed pro cam at 140 new.

.

 

[SoCalCruising]

You are getting wildly different advice, which may not be obvious to you. A Stock HO cam is 224/216 at .050, 116.5 LSA, as I recall, a reverse split duration cam. These can work if you have an intake to exhaust ratio OVER .75 - AFR 165s would be heads that can use that cam and make good power up to 5500-6000 RPM. 57Fairlane has given the opposite advice at 212/222 at .050. Others are somewhere between these with respect to duration splits. Now any of these cams can make power IF they fit the flow characteristics of your heads. You REALLY can't make an informed decision until you know the flow numbers on your ported GT40s.

BTW, I'm not being critical of any of this advice. I'm just pointing out the wide variation seen, so far.

 

[57fairlane]

I have personally worked on motors that have had both.

So not too sure what you are getting at SoCal other than the motor in question has GT-40 heads.

Sorry all of my racing experience has been with foxbodies, but that is 99% of what is at the track in my area.

92 GT, full interior. 302 stock bottom end, ported Roush 200 heads, 1.7 crane roller rockers, shorties, pro-chamber, MACs, 3.73 & T-5 with a spec stage 3.

Put down 299 rwhp and 332 ft-lbs on the motor.
Ran a 8.03 at 83 mph on 275/50/15 MT ET Street Radials.

88 Coupe, 302 stock bottom end with the wolverine 1190 cam (212/222), Ported E7s, stamped steel rockers, long-tubes, off-road h pipe, flowmasters dumped, 4.10s & a T-5.

Ran a 7.81 at 88 mph on 26x10.50x15 ET Streets

So yes, good heads and you can get away with a lot more. And as I have stated before, most sbf cams are exhaust biased because they know stock exhaust ports leave a lot to be desired even untouched GT-40s.

 

[latamud]

Oh boy, i see a post war getting ready to starting. Hang on everybody, its gonna be a long ride! Just kidding. I better go to bed before I hurt someones feelings.

 

[steel1212]

I think the only thing socal is getting at is that there are 2 diffrent sets of cams being put on the table. One is intake bias the other exhaust bias. I would also make sure you switch gears as you'll really notice it then. When parts work well together good things happen. Look at my combo below it works very well together. The times where with a compression leak and no traction bars. This spring I'm kicking 12s butt!

 

[66newbie]

ok, for the new guys sake, maybe someone can explain the individual factors to consider ? If a guy has a stock motor, can he realize any benefit from a mild cam without upgrading anything else ? I would assume to get the most out of a cam you have to take ALOT into consideration and that's what I am trying to understand. I understand it's a complicated subject, just trying to understand.

 

[SoCalCruising]

For any given combination of intake system, heads, and exhaust, and given that the desired powerband is known (e.g., max. hp/tq at 4200/5800RPM, broad vs. narrow torque curve) there is one best cam. I'm ignoring hydraulic vs. solid cam, flat tappet vs. roller, and some other stuff, but I hope you get the idea. If we can agree on this premise, then you can see that you must understand the characteristics of the intake, heads, and exhaust in order spec a cam that will meet your powerband goals.

The other issue is that none of us, I suspect, have the $$$ to hire a dyno for a week and test a boatload of cams to see what grind works best with our own combos. So, no offense (really), but the anecdotal data in this thread isn't helping much - evidenced by the widely different grinds mentioned. What we CAN say is what performance we have with the cam we have, but we have very limited knowledge of wheter or not another grind would be better - I mean better all over the power curve. Now, once you have a "best" grind, given combo and goals, if you change the combo, or if you change the powerband goals, another grind becomes "best".

Take this as an acedemic exercise. There is no flaming going on on my part. I am just pointing out what I believe to be some problems with this discussion as it is being conducted.

66newbie: to the extent that your cam is not optimized for your combo and goals, yes you can improve performance with a new cam. However, if you really want a clear jump in performance, you should choose intake, heads and exhaust that match your goals and then get a cam that optimizes the performance of the motor.

Personally, I have a 331ci motor with a ported Stealth intake, AFR 185s, Doug's Tri-ys, and my performance goals of peak hp/tq at 4500/5800RPM and a broad torque curve. I took this combo and my goals to Ed Curtis and he spec'd a cam for me. It was within 2-3 degrees duration and one degree LSA of what I would have spec'd, but I fully expect that Ed's experience will yield a better cam than mine would have been. I expect to fire this thing up in January and then I'll find out how good a job was done.

 

[D.Hearne]

You are getting wildly different advice, which may not be obvious to you. A Stock HO cam is 224/216 at .050, 116.5 LSA, as I recall, a reverse split duration cam. These can work if you have an intake to exhaust ratio OVER .75 - AFR 165s would be heads that can use that cam and make good power up to 5500-6000 RPM. 57Fairlane has given the opposite advice at 212/222 at .050. Others are somewhere between these with respect to duration splits. Now any of these cams can make power IF they fit the flow characteristics of your heads. You REALLY can't make an informed decision until you know the flow numbers on your ported GT40s.

BTW, I'm not being critical of any of this advice. I'm just pointing out the wide variation seen, so far.

You sure about those GT/HO duration figures? I read the same in Ford's 5.0 book, but else where I've read that was a misprint and it's a single pattern cam with the advertised figures being 276/276. The F4TE cam is a split with 256/266.

 

[SoCalCruising]

I've never degree'd one and can only say what I've read about the HO cam. So, no, I'm not sure. It is curious that Ford would do that (reverse split) since the alphabet cams are single pattern. Do you know what the duration numbers are at .050"?

 

[D.Hearne]

The Ford book doesn't list the @ .050 figures. I too, wondered why they'd use a cam with a bias toward the intake, when it's painfully obvious that the exhaust needs the extra help. The F4TE is biased toward the exhaust and with 1.7 rockers, exceeds the GT/HO in lift there and equals the intake figures. Good cam with a carb and a 4 speed.

 

[mtbdoc]

Agree with the plan to spend a few $ and get input from Ed Curtis.

As an aside, Ed bought a GTO so we have him doing his thing for the LSx side of the aisle as well

 

[Z06killinSBF]

H.O. cam has .440 lift. The thing to do with the H.O. cam is to run the 1.73 roller rockers. That gives it close to about .460 something lift. Not bad with the mild GT-40 heads. You never stated what GT-40 heads they are. X, P, iron, aluminum. Since you stated about milling the heads, run the thinnest head gasket you can get. Also gander at the Anderson Ford Motorsport cams. I would recommend the "N-41" cam. There is a post on the corral that has the cam specs.

The E-cam is a great cam if you dont plan on being in serious racing. I made lots of power in it's day. Alittle dated for the track but still great on the street. Also look at the Trick Flow stg 1 cam. 221/225, .499/.510. Same as E-cam with more exhaust help.

The Ford head designs suck on the exhaust. Get a cam that "helps" the exhaust flow.

 

[57fairlane]

It is curious that Ford would do that (reverse split) since the alphabet cams are single pattern. Do you know what the duration numbers are at .050"?

Emissions control

I am pretty sure the stock cams in the E7 blocks at .050 are 208/204 on a 114 or 116. But the .444 lift is right on, its in the FRPP catalogs.

 

[SoCalCruising]

Thanks 57Fairlane.
Like D.Hearne, my info came from the 5.0 book. The specs were also quoted in a Car Craft article, but, when I checked, they also referenced the 5.0 book (sigh). I had thought that they may have degreed it, but no.

 

[D.Hearne]

Can't see where giving the exhaust less duration would help emissions. Especially where the F4TE got more duration and was a cleaner engine both in the pickups and the Explorer motor.