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| | | | Joined: Jan 2019 Posts: 24 'Bolter | | 'Bolter Joined: Jan 2019 Posts: 24 | I am looking at a gmc 302 with a howards F298 camshaft. The cam came from patricks truck parts.
Has anyone here run one on the street it appears to be a pretty wild cam for street use ??? | | | | | Joined: Feb 2004 Posts: 29,875 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,875 | Unless you've got the timing card that came with the cam, the only way to evaluate it will be with a degree wheel and a dial indicator. Anything approaching 300 degrees of duration on either intake or exhaust is probably too hot for regular street driving.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Apr 2010 Posts: 245 'Bolter | | 'Bolter Joined: Apr 2010 Posts: 245 | F298 ??
Isn't that a 235/261 cam? | | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | It may be a grind number, not a part number. | | | | | Joined: Jan 2019 Posts: 24 'Bolter | | 'Bolter Joined: Jan 2019 Posts: 24 | It's a howards F298 gmc camshaft that patricks truck parts use to sell. I have the cam card if I knew how to post it I would. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Take a digital picture of it, click on ‘use full editor’, click on ‘attachment manager’ , click on ‘ select a file to attach’ , click on ‘ select a file to attach’ click on ‘file’, click on ‘done’. Or, get some kid walking by to show you!
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Feb 2004 Posts: 29,875 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,875 | The card should list such specifications as intake and exhaust valve opening and closing degrees, cam lobe lift, valve lift, etc. The "298" part of the cam number might be the valve open duration in degrees of crankshaft rotation, which would be a pretty radical cam to run on the street. Most "stock" cams will have duration numbers somewhere in the 250 to 270 degree range. A 300 or more degree cam will have low intake manifold vacuum, a choppy idle, and very low torque at low RPM. There will be lots of horsepower at high speed near full throttle, but the low speed performance will "inhale vigorously"! Long duration cams also need a high static compression ratio, big valves and ports, and a free-flowing exhaust system.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | "Long duration cams also need a high static compression ratio"
Did you mean "cams with late intake valve closure"?
Harley-Davidson 750 race engines used 310° cams with 5.5:1 CR for 25 years (intake closes @ 65° ABDC). | | | | | Joined: Feb 2004 Posts: 29,875 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,875 | Is Harley a stovebolt engine? This was a truck site the last time I checked.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Dec 2008 Posts: 1,922 'Bolter | | 'Bolter Joined: Dec 2008 Posts: 1,922 | I just proved your statement to be, at best, incomplete. Is a cam with the original factory intake closing point (very mild) but every other data point expanded, still "need" high CR? Your statement allowed for no exceptions, and I cited one.
What part of my statement is wrong? | | |
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