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Author Topic:   Higher RPMs with the mild cam?
streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-06-2003 03:23 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
I think I'm just going to get gears and a cam to add some power. I'm not changing my stock stall converter. My engine is a stock rebuild .030 over. With the new cam and gears, the engine will see higher RPMs than it does now, and more often. Since I'm not messing with anything else, besides cam, lifters, and eventually vavle springs, what cam would do good? What I'm saying is that I don't want to buy a cam that tops out at 7000 rpms b/c my engine probably wont hold up that high. And especially with the 3.25s or 3.55s vs. the 2.79s I have now, I will just be generally always running a little higher RPMs than right now. Basically, what are the components that would keep me from being able to rev to 6500 regularly? Also, what gears do you suggest to match the powerband of the cam you suggest?
Just tryin to learn as much about cams and gears before I decide so that I get the right thing.
Thanks

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Moneymaker
Administrator

Posts: 25883
From: Lyons, IL, USA
Registered: May 99

posted 04-06-2003 03:32 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
270S or H cam and some 3.80 gears if you have an 8 inch.

------------------
Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com

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streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-06-2003 08:19 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
Tell me if this is bs, but the desktop dyno shows only a 10 hp/ftlbs of a difference between these three comp cams: XE262H, HE268H, and M270H. It also shows around a 50 hp gain from stock with just changing cams. What do you think? What are some differences between these cams?

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Fastymz
Moderator

Posts: 18703
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 04-06-2003 08:22 PM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
I think that a 50hp gain with the right cam is about right.With good heads,intake and exhaust.
A differnece of 10hp at what RPM range?

------------------
SCOOP
oddly obsessed with big scoops on little Mustangs

2.26 60'S
14.9 @ 90.86MPH

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

https://mustangsandmore.com/ubb/Fastymz.html

[This message has been edited by Fastymz (edited 04-06-2003).]

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streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-06-2003 08:29 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
The curves are almost identical, just spaced out about 10hp/tq the whole length of the graph. The peak hp for all of them is just at 5000.

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Moneymaker
Administrator

Posts: 25883
From: Lyons, IL, USA
Registered: May 99

posted 04-06-2003 08:44 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
One of these days I'm going to see if I can bolt up a "desk top dyno" to an engine and see how much more power it makes.

------------------
Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00,'01,'02,&'03
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 04-07-2003 10:15 AM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by streetstang67:
I'm not changing my stock stall converter. My engine is a stock rebuild .030 over. I'm not messing with anything else, besides cam, lifters, and eventually vavle springs, what cam would do good? Basically, what are the components that would keep me from being able to rev to 6500 regularly?

We need to know what engine you are dealing with. Is it a 289/302, or something else?

You have a stock converter, but want to spin the engine 6500rpm. This will be a problem. Cams that like to rpm like that do NOT like stock converters.

Stock heads will also refuse to make much more than noise above 5000rpm, so camming the engine to spin much higher than that will only cause problems. The engine will be a dog down low due to the large cam, then when the cams comes on, the heads will be holding the engine back. It won't run right anywhere.

Cam the engine to match the rest of the combo. Stock converter and stock heads call for a cam that max's out around 5500rpm. On a 302, you're looking at around 210-218 @ 0.050" on the intake for a hydraulic. A 351W may get by with 4-5 degrees more.

ESPECIALLY for street cars, it's better to UNDER cam than overcam. 95% of the time, if you're torn between two cams, you'll be happier with the smaller one.

Be SURE to use the recommended valve springs anytime when changing cams. Don't wait for later. Do it NOW. Stock springs are very weak... especially after already being compress a bazillion times from thousands of miles of use. NEW stock springs can be floated with a STOCK cam... add a more aggressive aftermarket cam, and the valves are bouncing all over the place.

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

[This message has been edited by n2oMike (edited 04-07-2003).]

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streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-07-2003 04:04 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
What are some diffences between these two cams? HE268H, XE262H? Heres the specs...what are some differences besides numbers?

HE268H:
Specifications:
* Advertised duration: 268 intake/268 exhaust
* Duration at .050 in. cam lift: 218 intake/218 exhaust
* Gross valve lift: .456 in. intake/.456 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,500 to 5,500

XE262H:
Specifications:
* Advertised duration: 262 intake/270 exhaust
* Duration at .050 in. cam lift: 218 intake/224 exhaust
* Gross valve lift: .493 in. intake/.500 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,300-5,600
* Idle: Smooth
* Excellent response, good mid-range, stock converter, 3.23-4.10 gear

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streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-07-2003 05:40 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
one more thing: How lumpy of an idle will I get with either of these cams?

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MidLifCrisis
Gearhead

Posts: 466
From: Frederick County, MD
Registered: Oct 2001

posted 04-07-2003 07:34 PM     Click Here to See the Profile for MidLifCrisis   Click Here to Email MidLifCrisis     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by streetstang67:
one more thing: How lumpy of an idle will I get with either of these cams?


Streetstang67: the XE262H has a very distinct idle. It doesn't sound like a Harley with that lazy lope, but it doesn't sound stock either. With rather loud turbo mufflers, my Chevy-loving neighbor asked me what I had done to my Mustang to get it to "sound right". I have no problem out of the hole even with the 2.79 rear, as for topend haven't a clue- I just rolled 100 miles on the rebuild over the weekend, so am still taking it easy.
This is all I can offer. I have no experience with the HE268, I can only offer that am pleased with the XE262. If you live near Frederick, MD I would let you see first hand. Charlie

[This message has been edited by MidLifCrisis (edited 04-07-2003).]

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Fastymz
Moderator

Posts: 18703
From: Reno Nv USA MEM#1240
Registered: Apr 2001

posted 04-07-2003 07:46 PM     Click Here to See the Profile for Fastymz   Click Here to Email Fastymz     Edit/Delete Message   Reply w/Quote
HE286H cant be that lumpy thats about the same cam I just put in my car.It is smooth as can be.It idles better then ever now.There is no sign of a cam at all.Hey it's a SLEEPER now.

------------------
SCOOP
oddly obsessed with big scoops on little Mustangs

2.26 60'S
14.9 @ 90.86MPH

65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede.

https://mustangsandmore.com/ubb/Fastymz.html

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 04-07-2003 08:43 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Fastymz:
HE286H cant be that lumpy thats about the same cam I just put in my car.It is smooth as can be.It idles better then ever now.There is no sign of a cam at all.Hey it's a SLEEPER now.

But yours is in a 351W. It will sound a bit 'lumpier' in a 289/302. (if that's what he has)

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

[This message has been edited by n2oMike (edited 04-07-2003).]

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streetstang67
Gearhead

Posts: 397
From: SC, USA
Registered: Nov 2002

posted 04-07-2003 09:16 PM     Click Here to See the Profile for streetstang67   Click Here to Email streetstang67     Edit/Delete Message   Reply w/Quote
MidLifCrisis,
I don't live near MD, so I cant witness it first hand...but a sound clip would be cool if you had the means of putting it on the web.

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