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  #1 (permalink)  
Old 11-29-2008, 05:31 PM
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confused about camshafts (SBF)

OK, I’m getting back into more traditional hotrodding after many years of sitting on the sidelines. Having all the kids through college helps! But I’ve got to admit that things have gotten a whole lot more complicated since I’ve been gone!
My new project looks like it will be a 1984 Ford 5.0 engine, coming out of a Grand Marquis. The AOD might be part of the package, since I understand that one can make these fairly stout with a little work.
I’m not looking for drag strip performance; in fact I’m not even sure what it’ll go in. I have lots of choices from a friend’s “dead car pasture”, so I’m not sweating it. What I really want to understand better is all my choices when it comes to camshafts.
The specs that still matter are intake/exhaust duration @ .050 lift and cam lobe separation angle, right?
When I look back at the camshafts available in the 70’s when I was last seriously getting greasy, there weren’t that many choices. But now, holy s**t!!!!
Just looking at Comp Cams, for instance, I see “computer controlled” and “thumper”. OK, I get both, and I get that “thumper” is a line of camshafts that make noise, not power, so THAT’s out of the question. But I’m expecting to MegaSquirt the engine, so the comp-controlled ones with large LSA is understandable. But the profile mixes are off the charts.
I remember the single profile line of cams, each cam in the line stepping up 10* of duration; and usually one line of dual profile that offered 10* more exhaust than intake, and that was what you ran on “muffled” cars. Got that.
So you would have a line of single profile cams, and would choose a cam with 196* of duration, or one with 206*, or 216*, or 226*. In the dual profile you could choose a 196/206, a 206/216, or a 216/226, and so on.

But help me through this mess.

1. COMP Cams 31-255-5 206/212, 114* LSA 1000-5200 rpm
2. COMP Cams 31-230-3 206/212, 110* LSA 600-4800 rpm
3. COMP Cams 31-234-3 212/218, 110* LSA 1000-5200 rpm
4. COMP Cams 35-216-3 212/212, 110* LSA 1200-5200 rpm
5. COMP Cams 31-416-3 203/216, 110* LSA 1000-5500 rpm
6. COMP Cams 31-409-3 211/223, 110* LSA 1600-5750 rpm
7. COMP Cams 31-238-3 218/224, 112* LSA 1300-5600 rpm
8. COMP Cams 35-218-3 218/218, 110* LSA 1500-5500 rpm

And THAT’s just from one manufacturer!!!!
Obviously I’ve settled on a goal of good midrange with a ~5500 rpm ceiling. At this target rpm range, I see little advantage in a single profile cam. And it seems that at least CompCams thinks that the difference in how well sbf heads breathe through their intakes and exhausts warrants a pretty consistent 6* difference in intake/exhaust timing. But what’s the deal with #6 (12* more exhaust) and #5 (13* more exhaust)? Under what circumstances would these cam profiles be advantageous?
Furthermore, when I compare #s 3 and 6, I have a tough time believing that decreasing the intake duration would actually bump the useful rpm range upward. How reliable are the manufacturer’s guidelines on this?
And furthermore, am I making this too complicated?

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Last edited by pstrbrc; 11-29-2008 at 08:05 PM.
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Old 11-29-2008, 10:30 PM
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Don't rule out the thumper series cams. Yes, the go rumpity rump, but they also make great power.
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Old 11-29-2008, 10:51 PM
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If you want to talk to one of the top camshaft designers in North America,call UDHarold brookshire at home,he can help you out,he made my custom roller cam and I am very happy with it.

#9 Dec 12th, 07, 3:44 AM
UDHarold
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Re: Pri

--------------------------------------------------------------------------------

Everyone,

Now I've done it........
I am now selling ALL of my previous work from 1980 til now, and into the future.
If you want an original UltraDyne, or one of my Lunati or VooDoo cams, or one of my Custom Camshaft Rollers, or what I may be doing in the future, please give me a call.
I will be getting a new phone number by the first of January, but my home phone number is still 662-562-4933.
I was a little late getting back from PRI, my son had scheduled impacted wisdom teeth surgery for Monday morning, and wanted me to be his designated driver, so I ended up staying a couple of extra days down there.
Unfortunately, I saw very little of the show, as most of my time was spent discussing 'deals' with cam companies.
Most of the valve train components will be from Lunati, as they have the good Morel lifters, including micro-polished ones, and with oil holes on the faces, and the Pacalloy springs, including the BeeHives.....

If I made it, I sell it.

UDHarold

PS---New designs are being worked on.


Hope this helps
Guy
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Old 11-30-2008, 12:21 AM
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SBF Cams

Quote:
Originally Posted by pstrbrc
OK, I’m getting back into more traditional hotrodding after many years of sitting on the sidelines. Having all the kids through college helps! But I’ve got to admit that things have gotten a whole lot more complicated since I’ve been gone!
My new project looks like it will be a 1984 Ford 5.0 engine, coming out of a Grand Marquis. The AOD might be part of the package, since I understand that one can make these fairly stout with a little work.
I’m not looking for drag strip performance; in fact I’m not even sure what it’ll go in. I have lots of choices from a friend’s “dead car pasture”, so I’m not sweating it. What I really want to understand better is all my choices when it comes to camshafts.
The specs that still matter are intake/exhaust duration @ .050 lift and cam lobe separation angle, right?
When I look back at the camshafts available in the 70’s when I was last seriously getting greasy, there weren’t that many choices. But now, holy s**t!!!!
Just looking at Comp Cams, for instance, I see “computer controlled” and “thumper”. OK, I get both, and I get that “thumper” is a line of camshafts that make noise, not power, so THAT’s out of the question. But I’m expecting to MegaSquirt the engine, so the comp-controlled ones with large LSA is understandable. But the profile mixes are off the charts.
I remember the single profile line of cams, each cam in the line stepping up 10* of duration; and usually one line of dual profile that offered 10* more exhaust than intake, and that was what you ran on “muffled” cars. Got that.
So you would have a line of single profile cams, and would choose a cam with 196* of duration, or one with 206*, or 216*, or 226*. In the dual profile you could choose a 196/206, a 206/216, or a 216/226, and so on.

But help me through this mess.

1. COMP Cams 31-255-5 206/212, 114* LSA 1000-5200 rpm
2. COMP Cams 31-230-3 206/212, 110* LSA 600-4800 rpm
3. COMP Cams 31-234-3 212/218, 110* LSA 1000-5200 rpm
4. COMP Cams 35-216-3 212/212, 110* LSA 1200-5200 rpm
5. COMP Cams 31-416-3 203/216, 110* LSA 1000-5500 rpm
6. COMP Cams 31-409-3 211/223, 110* LSA 1600-5750 rpm
7. COMP Cams 31-238-3 218/224, 112* LSA 1300-5600 rpm
8. COMP Cams 35-218-3 218/218, 110* LSA 1500-5500 rpm

And THAT’s just from one manufacturer!!!!
Obviously I’ve settled on a goal of good midrange with a ~5500 rpm ceiling. At this target rpm range, I see little advantage in a single profile cam. And it seems that at least CompCams thinks that the difference in how well sbf heads breathe through their intakes and exhausts warrants a pretty consistent 6* difference in intake/exhaust timing. But what’s the deal with #6 (12* more exhaust) and #5 (13* more exhaust)? Under what circumstances would these cam profiles be advantageous?
Furthermore, when I compare #s 3 and 6, I have a tough time believing that decreasing the intake duration would actually bump the useful rpm range upward. How reliable are the manufacturer’s guidelines on this?
And furthermore, am I making this too complicated?
Stop by www.sbftech.com and talk with Jay Allen, this is a No Bull site for Ford Small Block Guys unless you are really hung up on Comp Cams decals.My '54 also has a '84 302 and AOD.
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Old 11-30-2008, 01:17 AM
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You need to make some choices on the type of car its going in, weight of the car is important. Horsepower level you want to build the engine to achieve not to mention torque converters, axle ratio etc.etc.etc.

Things haven't changed any since you have been tinkering, they have just been fine tuned for specific setups.

Look at it from this perspective, cam manufacturers realized that most rodders these days buy a sports model with a specific engine and then they designed a cam to work with the most common setups guys built these engines too.

For example your 5.0 was common to the Mustang, if your going to build the engine up you could do a lot worse by selecting a package from Ford Motorsports as long as your follow their specs for the setup. I would rethink the Megasquirt direction only because a factory setup will handle the cams you are looking at and be a lot easier on the pocket book.

The B303 cam was a pretty popular cam choice from FM and works well with just a header addition and some 3.50 gears. Expect around 300HP in the factory configuration with those addons. Just remember fuel injection will dictate how much air you can pass if your going to stick with a factory setup.

One of the guys I know at our road race track has a tube frame fiberglass replica 66 GTA Mustang, he runs an AL Ford Motorsports block and a GT40 intake and B303 cam and turns out 370+HP all day at the track...its so reliable he just changes the oil after every race and he turns it too 7500 on every shift. As far as I know it has never been apart, its over 6 years old now!

Could he make more HP? No doubt...but the thing has gobs of torque and can spin the tire at any rpm in any gear, his mild build up has a lot of advantages on the track that translates into great street performance too.

Just forget the big HP numbers and build a strong torquey engine thats fun to drive and flexible enough to putt with, if you want smoke shows put in some 4:11 gears and spin away.

I see so many guys get carried away with making the big numbers up top that the thing becomes a PITA below 4000 rpm and its no longer fun when it falls on its face below a 3500 stall speed converter.

If you want to save some money go look at the Performer RPM series and go with a carb, you won't be disappointed. Cheap HP in anybody's book, just follow the MFG's recommendations for setup.

In the old days you had to design the package and figure it all out trial and error or build whatever they built in a magazine, now it comes in a box with instructions!
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Old 11-30-2008, 09:18 AM
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Being a Ford guy and having done this several times I think I can give you some meaningful generalities.

There is a LOT of difference between 5.0s of carbed, fuelie, and HO status.
Biggest thing is heads (all tiny ports and valves) and firing order of the cam. Much of a cam will cause valve/piston clearance concerns.

I have taken some CrownVic LoPos (150 hp) and installed carbs and they run well without cam changes.
Using 1.7 rocker arms is a good way to get lift and pseudo duration with a more mild cam.

Yours is flat tappet and as for cams, I suggest staying in the 210* max @ .050 range single pattern cam regardless of vehicle. Most fuel injection will recommend a LSA lobe separation angle. Carbs like 108-109* but fuelies need 114 or more to reduce overlap (hurts scavenging), especially if it is a speed density system.

IMO the heads are so restrictive even when smoothed port texture, that split duration cams with more exhaust duration is NOT what to do.
Here's why = split duration cams are "desired" because they make a broad flat torque curve.... they say...... but it is broad and flat because the split duration cam takes away from the low/mid range torque for a gain in upper rpm, making the curve flatter by cutting off the middle.

Unless you are going to buy $1500 heads, all SBF are small cube, low torque, restricted breathing heads and taking away from the low/mid range to gain 5-10 above 5000 rpm is wasted effort.
HEY, even the factory Mustang HO with SFI uses a cam with more INTAKE duration, not exhaust. Ford put a lot of thought into the cams and made some great running small block engines from 88-93.
A stock cam HO with TE iron heads will get clost to 400 hp if done right, but it is too much rpm with too low of mid range torque to be fun to drive.
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Old 11-30-2008, 10:22 AM
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If this is just to be a driver use one of the ford racing cams with a 351W firing order and use a computer from a 89 Mustang. Ford has or had a cam part number #M-6250-M50 208/224 .453 .453 115.5 LSA Hydraulic Flat tappet. Its discontinued now but I bet there are still some out there for dirt cheap. You would probably be light years ahead finding a 5.0 from an 89 and up stang. They have roller cams, forged pistons and far better heads than the pre 87 engines.

Here is a link to a couple of places in Kansas that may have old stock ford cams if you decide to go that route.
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Old 11-30-2008, 10:49 AM
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Quote:
Originally Posted by Greg T
Don't rule out the thumper series cams. Yes, the go rumpity rump, but they also make great power.

They make okay power, not the most powerful cam by a long shot- they also lower your mileage though, if you're into that sort of thing.
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Old 11-30-2008, 11:54 AM
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the Crane cams site gives a little bit better definition, why and what for and what is needed with each different grind....
(click on a few)

http://www.cranecams.com/index.php?s...Size=302%20C.I.

go back and look at those street comps cams grinds....
the lifts are are all different,,,
even though the durations are close,,,
to better match the heads and pistons combo

you need all the choices to cover all the markets....
mud truck/rock crawling/junior stock/marine/1/8th mile only/etc/etc

Last edited by red65mustang; 11-30-2008 at 12:09 PM.
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Old 11-30-2008, 08:02 PM
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Thanks, guys. You've given me good stuff to get started with. I think I can do this now!
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