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Author
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Topic: 351C cam advise
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: Apr 2001
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posted 04-11-2001 01:21 PM
   
I am in the middle of a rebuild and am looking for "MORE POWER" while the motor is apart like most gear heads. I am not going to use port plates from all the negitve responses I have got. The cam that I had in the engine that Crane recomended a few years back is a hyd. flat w/specs of 222/234 duration @ .050 with advertised @ 278/290 with valve lift @ 539/534 and lobe seperation @ 114. The engine is a 351C 4V with about 10.3 compression ratio, Hooker Super Comp headers, MSD ignition, roller rockers, stock carb/manifold(thinking about changing), 3.55 gears, auto trans w/2500 stall(want to change to a milder stall). The car is a street driven 73 fastback weight is about 3800. I ran the car at the track last fall running low 14's. I was thinking about a different cam for more low end torque and a Performer intake with a 750 vac. secondary carb.(had a 600 and had better performance with stock carb). Any ideas or comments? ------------------
Mark from Detroit
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 04-11-2001 01:24 PM
Comp Cams 268H is a great compromise camshaft.  ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: Apr 2001
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posted 04-11-2001 01:37 PM
Alex, Do you have the spec's of the 268H cam. What do you think of the cam spec's of the cam I have?
Mark
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Mark from Detroit
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 04-11-2001 07:46 PM
Mark, your Crane unit is faily aggressive for the street with your mild converter. The COmp 268H has an advertised duration of 268 and a duration at .050 of 218 and lift of .494. CL is 110. This cam will be much better suited to a lower stall speed and girlyman gears. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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n2oMike
Gearhead Posts: 1511
From: Spencer, WV
Registered: Jan 2001
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posted 04-11-2001 09:31 PM
The lobe seperation of the cam is what reaches out and grabs my attention.4bbl Clevelands have overly huge intake ports that provide low velocity. These engines benifit from tighter lobe seperation angles, and the 114 degree seperation of your current camshaft is on the extremely wide side. The extra overlap provided by the tighter lobe seperation, will pick up the mixture velocity and give the engine some more punch. The intake duration is the main factor in determining the rpm range of the engine, and 222 is about right. A little extra exhaust duration is a good thing with these heads. I'd go with a similar duration cam with a lobe seperation around 108-110 degrees. I'd leave the 2500 rpm converter in place. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367 [This message has been edited by n2oMike (edited 04-11-2001).]
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: Apr 2001
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posted 04-11-2001 10:23 PM
Thanks for your input Mike, I also thought the lobe seperation was a little high myself. It is hard to compare cams if you dont have a catalog with all the specs and also go with a recomendation from a cam tech advisor.
Mark
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MrXerox
Gearhead Posts: 322
From: Oklahoma City, Oklahoma
Registered: Nov 2000
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posted 04-12-2001 02:12 AM
Mark, had a 222 @ .050 with a .542 single pattern cam, a 2500 stall, a performer intake and a 650DP and all the goodies you have and was not happy at all with the performance. One thing I have learned after all this money wasted is that Clevelands like HUGE cams, single plane intakes and big stall converters. Going with a solid roller 244 @ .050 .624, X-Cellerator intake and a 3500 stall this time around I dont think there is such a thing as "low end torque" on a 351C 4V motor. Unless you use port plates of course (tsk tsk) NOT!
Try this link for a general idea. All the cams were put into desktop dyno 2000 with the real flow specs of stock 351C 4V heads (unmodified) not saying its totally correct but it will give you a general idea...http://www.geocities.com/fordracing68/cam.html [This message has been edited by MrXerox (edited 04-12-2001).]
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Scott (69Mach)
Gearhead Posts: 445
From: Walnut Creek, CA USA
Registered: Jun 99
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posted 04-12-2001 09:50 AM
Steve has a good cam comparison chart on his web site:
http://www.geocities.com/MotorCity/Flats/3845/camchart.html
I have a spreadsheet with similar information, but couldn't get it to post without scrambling the tables. You've got a 4V 351C that was designed to spin higher rpms. I'd build it that way instead of working on low rpm torque. Keep the stall converter, get a big cam and rear end gears, put on a Blue Thunder dual plane and a 750 cfm carb. You'll get bigger grins that way.
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kid vishus
Gearhead Posts: 4357
From: middle of NC
Registered: Oct 2000
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posted 04-12-2001 10:01 AM
If you want more low-end torque, put 2 barrel heads on it. Port 'em a little, put good valves in 'em, and you will have low end power.
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Hans olsson
Gearhead Posts: 290
From: Sweden
Registered: Apr 2000
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posted 04-12-2001 11:21 AM
Hi Mark, Im not sure if this will help, but anyway.We have a comp cam hyd 260/[email protected] valve lift @427/450 lobe sep 108. Carb is 780 holley and ford alu intake.D1AE heads(closed chamber) TRW pistons stock con rod and crankshaft. Stall speed 5500 shift rpm 7200. Rear gears is 5.43. This is a nhra stocker. New parts for this year is ram air and a new carburetor Hans. ------------------
-71 351c Mustang E/SA 11.92-110 mph.
-87 volvo daily driver.
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 04-12-2001 11:32 AM
More power and better drivability or just out and out MORE POWER? Now I'm confused  . I thought that Mark wanted to reduce his stall speed and pick up his bottom end to compensate. Oh well, I'm out of this one now. I'll leave the advice to the experts. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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Scott (69Mach)
Gearhead Posts: 445
From: Walnut Creek, CA USA
Registered: Jun 99
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posted 04-12-2001 12:52 PM
My point was that the 4V was built to run. Seems like a waste to build it otherwise. If he wants more low end and drivability, go with Kid Vishus' recommendation for 2V heads.
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n2oMike
Gearhead Posts: 1511
From: Spencer, WV
Registered: Jan 2001
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posted 04-12-2001 01:32 PM
He's already got the intake and headers for the 4bbl heads. A tighter lobe seperation cam with moderate duration will add a lot of punch to the engine's midrange. The 2bbl open chamber heads will kill quench and drop the compression too much. If he was wanting to go to the trouble of changing the heads, headers, and intake... I'd recommend a set of Aussie heads. But, with his current 10.3 compression, the right cam will have plenty of low-end and mid-range. Alex mentioned 218 @ 0.050", I said his 222 @ 0.050" was in the ballpark. Anywhere right around that range with a tighter lobe seperation will do nicely. I'd still keep the 2500 stall. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
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Mark From Detroit
Journeyman Posts: 29
From:
Registered: Apr 2001
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posted 04-12-2001 01:59 PM
I do want to keep the 4V quench heads at this point. I guess i am trying to get the motor to perform well across all rpm ranges with the right cam if that is all possible. Mark ------------------
Mark from Detroit
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 04-12-2001 03:13 PM
I'd keep the converter also Mark/Mike and get some 3.90 to 4.11 gears. ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
IP: Logged |
kid vishus
Gearhead Posts: 4357
From: middle of NC
Registered: Oct 2000
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posted 04-12-2001 08:32 PM
The headers would fit. I have Hooker Super Comps for the 4v heads on my racecar and it has 2v heads on it. And they seal fine.
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