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Discussion Starter #1
I finally found the specs of the cam I have in my Mustang.

The specs are:
cam lift int .278
cam lift exh .283
valve lift int .444
valve lift exh .452
dur @ .050 206/221
dur @ .006 283/304
lobe C/L 115
overlap 60

And from other cam specs that I have looked at, none of them really come close to matching mine. For one thing, the duration difference between intake and exhaust seems like a lot, and overlap seems high as well.

Cam experts, what does this all mean? Is it a crappy cam or did that old engine builder whom I purchased it from know something about 351w cams that most don't? If I were to cross it over to a Crane or other cam, which one would it be like?

Thanks for your help folks.
 

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It's a pretty mild one and close to stock I would imagine.

The wide split is meant to address the traditionally poor exhaust on stock Ford heads.

How does/did it perform? Are you considering a cam change?
 

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Discussion Starter #3
It works fine, I have no problems with it. It has a slight rumble to it (no noticable lope), but runs fairly smooth overall. My Mustang is my daily driver, so I don't think I will be doing a cam change anytime soon, especially since gas prices are as high as they are. I am basically trying to find out why the cam specs are so different (the duration split especially) from after market cams.

I have just recently ported my heads and I noticed a nice improvement in response, power, and revability (now I am making up words...). So I am also wondering if the cam is reducing performance/economy now. I know other things on my Mustang are probably reducing performance (crappy generic mufflers, stock intake), but is the cam too?
 

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If you're happy with it and it performs satisfactorily for your needs that's a good thing.

Your porting efforts have undoubtedly improved the flow, but they are still the stock heads and without some major improvement in flow (ala blkfrd's method) the split duration is doing you good.

I'd step up the intake and exhaust systems for some additional performance.
 

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The cam seems about the same as the edelbrock performer (448/472 lift, 206/216 duration) Thats what I have in my 351w, and my heads are 1.94/1.60. I added some crane roller rockers, and that added a nice little boost as well. As for fuel economy, I get about 14 mpg out of 87 pump gas, which is not bad considering I have a mix of highway and city driving, and I open those back barrels a lot. If I drove more responsibly, I get about 16 to 17 mpg. But that's no fun! I get a little rumble from my cam as well, very small lope to it. ( I have headers, 2 1/4 dual exhaust, and 2 flowmaster mufflers) I am more than happy. But if you want more, try the edelbrock performer rpm, with matching intake. Fuel economy will suffer with this one, as it has a .512 lift, I believe. If you are not happy, I would suggest going bigger. ( just my opinion, I say the hell with fuel economy) Hope I was some assistance.
 

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Discussion Starter #7
Jay...

Your engine seems to be built like mine, only your's is better ;). I get the same amount of gas mileage too, only I have to run it on 91 octane (which doesn't work very well on a 10.7 to 1 CR, 93 would be better, 100+ would be best). I have 2.25" exhaust pipes as well, but no flows. But one thing that does differ, I like fuel economy. Paying $2.40 for a gallon of gas gets old quick. I think I will be staying with my current cam for awhile, atleast until I can get another car to be my daily driver. Thanks for the help.
 

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Don't you need longer pushrods with the 1.7 ratio, Art? I was curious about the 1.6 vs. 1.7 ratio rockers myself. Did you do this? If so, what kind of gain could you get going from a 1.6 to a 1.7?
 

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Discussion Starter #9
Art....

Considering my cam profile, would I gain anything from 1.7 rockers other than increased valve train wear?
 

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Dave, 87 octane gas in central florida is 1.80 a gallon. Big difference. I did not notice you were in California. I'm sorry, at THAT price, mileage matters. By the way, what did you set your initial timing at? You have electronic ignition, right? My timing is set at 14. She restarts a little slow when hot if I bump it up to 16. 14 seems perfect, and she runs wonderful on 87. I tried 93 for the first 2 tanks since I rebuilt the motor, and I did not notice a difference between 87 and 93.
 

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Discussion Starter #11
You are lucky. Mine won't run on anything less than 91, and even then I have the timing pulled WAY back. I think I am running about 8º initial, and I had to modify my mechanical advance in my distributor to only advance 19º or 20º. So my total advance is less than 30º. If it is any higher, the motor pings to high heaven. And I have tried everything to get it to stop pinging, and backing the timing down is the only thing that works.

I once put a gallon of alcohol in the tank, for added octane boost, and it ran sooooo much better. But alas that is not cheap either. For special events I will do that again, but for everyday driving, I'll have to stick to the de-tuned setup and 91 octane crap. As far as fuel quality goes, California sucks!
 

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My advance is the normal 24 degress, putting my total at 38. Mallory says the total should be 38 to 42. I can advance my timing to 18, and the power difference is amazimg. I can still run on 87 without a problem, it just gives me hassles restarting hot. I keep a timing light in my trunk, in case I want to go to the track. Cali must have crap gas. But 30 degrees total seems really low. What do you have for an ignition system, and how old is it?
 

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Discussion Starter #13
I am using a pertronix, stock distributor, Ford 9mm wires, and a hot coil from a newer Mustang (TFI is what its called, I think).

My ignition system works fine, its just that I can't advance the timing too much otherwise the motor pings bady at higher rpm's. I think I may have closer to 11:1 compression because of the engine rebuild (bored it out .030), stock was 10.7:1. Heat also plays a factor in my pinging problem. If the engine gets heat soaked from driving around town or sitting in traffic, if I goose the throttle, it might ping a little. But as soon as I flush the hot air out, it will go WOT with no problems. It is always on the bitter edge of detonation, it sucks.
 

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Don't you need longer pushrods with the 1.7 ratio, Art? I was curious about the 1.6 vs. 1.7 ratio rockers myself. Did you do this? If so, what kind of gain could you get going from a 1.6 to a 1.7?
Longer pushrods? No...
Have I done this? Yes!
You get more valve lift, slightly more duration.

Cam lift x rocker arm ratio = valve lift
 

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Thanks for clearing that up, Art. By the way, Dave, my motor is bored .060 over, with no major cooling problems. I have a 6 blade flex fan, and I put a 16" electric fan in front of a 4 core radiator. I have it rigged to a 35 amp toggle switch on my dash. When I am in traffic, and the motor starts to get hot, the extra fan gets flipped on. It does wonders. I think my compression ratio is about 9.5 or 9.7, not too sure. An 11 to 1 ratio would explain the extra octane need. I am far from an expert. I think I put my motor together, and kind of got lucky on the block/parts combo. If it works good, I don't try to find out why. I only research when something goes wrong! Sorry if I didn't help that much. I'm just spitting out ideas, based on problems I have had. I have never had your problem. Good luck, though.
 

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Discussion Starter #16
If I were to go to 1.7 rockers, what qualities of the motor would change? More HP? More torque? Both? What about fuel economy? Will it lope?

I ran the numbers real quick and the intake lift would change to .472, the exh to .481. A noticable improvement, but would it be in the car?
 

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You will have slightly more HP and torque, everythings a trade off, so your gas mileage will suffer slightly.

It's not a "plug and play", you have to convert to 7/16 rocker studs and watch for push rod/head interference...

Will it be worth the trouble? dunno...
 

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Dave,
Yours is a stronger-than-stock cam, but still very mild. It should be fine for daily driving w/ good low range torque (to 4500+) and decent gas mileage. You like it right?
I did a cam upgrade from a cam like yours to another hydraulic and here’s the little story and findings. Came real close to going with a roller cam like Art uses, but would I have been happier? Hmmm, maybe yes maybe no?

In my 351W and I had the first Crane cam below for 5 years than switched to the second one which is called “strong” performance and has good lift but still is a bit more tame than the common Performer RPM. This is with performer aluminum heads - .190 valves. I have a 9:0 compression ratio, and it never pings on 89 Octane – nice - but I know costs me some potential horsepower. I’ve got a lot of mechanical advance in there above about 2800 rpms, maybe 40 degrees.

CAM 1
http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=443941&B1=Display+Card
CAM 2
http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=443901&B1=Display+Card

Results - vacuum dropped from 18 to 14. Engine runs hotter, had to add a shroud and 6 blade fan. Gas mileage – same. Idle, added slight lope where none existed before, the idle exhaust note got noticeably louder (idles perfectly at 600 rpm). Low rpm torque is a bit stronger, but the bigger difference is from 3000 rpm on up. I think the 50 to 90 mph time was reduced by several seconds – definitely can feel it lunge hard above 4000 rpm. Probably enough to leave kbmwrs in that big block beasty car of his but who knows and I hope he isn't reading this.

This is a daily driver so to be honest, it doesn’t get wound up very often. After all, where can you go 90+ in the Bay Area, which is where the C4 will autoshift to 3rd with 3.25 gears. I’ll hold it to 100 if I want to get near red line in 2nd.

So, yeah, it is faster, but I’d say if your are happy and it runs well, then don’t worry about it. If you gotta have more steam, you can get it but how often you demand it is really the question. You can try Art’s 1.7 suggestion very easily w/ almost no disassembly, and it’d be interesting to see what it does.
K
 
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