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Cam choice

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3004speed
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Cam choice

Post #1 by 3004speed » Tue Mar 12, 2013 11:40 pm

Cam choice for 300 six.The truck is a 79 ford f250 4x4,new process 435 trans .The current motor has 9.5 compression,clifford intake and headers,holley 390 cfm carb and dui fist.The cam is a comp 268 (218 dur@.50)458 lift and 110lsa.The truck is very strong throughout all usable rpm range.At 60 mph I'm turning2300 to 2500 rpm.What I've noticed is when pulling a load(like a pontoon boat) the torque is not there.Fixing to have to change the cam and lifters due to a couple of bad lifters,I'm going to a clay smith setup and here is the two choices:480 lift 220@.050 108 lsa. 480 lift 208@.050 108 lsa. I'm looking for the power of the comp cam I currently have but one that has more grunt when pulling a load in the 1800-3000 rpm range. Advice or experience with these two cams would be greatly appreciated. Thank's

Harte3
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Re: Cam choice

Post #2 by Harte3 » Wed Mar 13, 2013 9:55 am

viewtopic.php?f=2&t=62982&start=0&hilit=Does+it+pull%3F

There is my experience with a Comp 260, Offy DP, Holley 1848, P&P head, EFI exhaust on an otherwise stock rebuilt engine.

JMO, the Comp 268 raises the working rpm of the engine to just beyond where it is practical for a working engine.
'83 F150 300, 0.030 over, Offy DP, Holley 4160/1848-1 465 cfm, Comp Cam 260H. P/P head, EFI exhaust manifolds, Walker Y Pipe, Super Cat, Turbo muffler, Recurved DSII, Mallory HyFire 6a, ACCEL Super Stock Coil, Taylor 8mm Wires, EFI plugs.

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StrangeRanger
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Re: Cam choice

Post #3 by StrangeRanger » Wed Mar 13, 2013 10:46 am

for low RPM torque you want short duration. Even 208°@.050 may be too much. I don't know about the Clay Smith cam but most of their competitors advertise cams in that range as having an effective which starts at 2000 RPM and goes up to 4500 or so.
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
2013 Hyundai Elantra Coupe (daily driver)

BIG 6 farmer
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Re: Cam choice

Post #4 by BIG 6 farmer » Wed Mar 13, 2013 4:43 pm

StrangeRanger wrote:for low RPM torque you want short duration. Even 208°@.050 may be too much. I don't know about the Clay Smith cam but most of their competitors advertise cams in that range as having an effective which starts at 2000 RPM and goes up to 4500 or so.
X2 on that. I would say, you need more like 260 or less advertised duration. Since you need to pull your Boat, both Camshafts you show are no better. My pick would be an Isky Mile-a-More, or one close to that. You didnt say if your running a heated coolant plate on the bottom of your Intake ?? In my opinion, that would make a big difference on your low end torque. If you dont have that, do that first. Before you change out the Camshaft :nod:
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

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MechRick
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Re: Cam choice

Post #5 by MechRick » Wed Mar 13, 2013 11:35 pm

The Comp 268 likes to run above 3000 rpm. I don't notice any power loss between 2000-3000 rpm with the big cam. Unless I'm trying to pull below 1500 rpm or so, I don't really miss the stocker.

I've set mine up to pull hills in fourth gear at highway speeds with an upshift to fifth on the downgrades and level ground. I imagine a shift to third raises the rpm too much to be comfortable on your four speed? Never had a NP435, but have had a BW T18 with similar ratios. I remember it didn't like third at highway speeds.

You have quite a bit of compression. It won't like a mild cam.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

3004speed
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Re: Cam choice

Post #6 by 3004speed » Thu Mar 14, 2013 10:05 am

Thanks for all the replies.Called clifford yesterday and he swears by his cam grind.Its 476 lift - 206@.050 110lsa.Power from idle to 5000 rpm.Close to Clay Smiths recommended 480 lift-208@.050 108lsa.I know Classic Inlines likes the Clay Smith cams.Thanks Again

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THE FRENCHTOWN FLYER
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Re: Cam choice

Post #7 by THE FRENCHTOWN FLYER » Thu Mar 14, 2013 12:51 pm

Interesting feedback on the Comp 268 Rick. I'm going to use one in my Anglia w/ a C4 / 9" w/ either 2.75 or 3.25 gearset. I hope it gives me a nice drive-in cruise night style lopey idle and still moves the 2300 lb car along the highway. At 2300# I can afford to give up some bottom end and still have lots of fun at the top of each gear. We'll see.
FORD 300 INLINE SIX - THE BEST KEPT SECRET IN DRAG RACING

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80broncoman
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Re: Cam choice

Post #8 by 80broncoman » Thu Mar 14, 2013 10:28 pm

3004speed wrote:Cam choice for 300 six.The truck is a 79 ford f250 4x4,new process 435 trans .The current motor has 9.5 compression,clifford intake and headers,holley 390 cfm carb and dui fist.The cam is a comp 268 (218 dur@.50)458 lift and 110lsa.The truck is very strong throughout all usable rpm range.At 60 mph I'm turning2300 to 2500 rpm.What I've noticed is when pulling a load(like a pontoon boat) the torque is not there.Fixing to have to change the cam and lifters due to a couple of bad lifters,I'm going to a clay smith setup and here is the two choices:480 lift 220@.050 108 lsa. 480 lift 208@.050 108 lsa. I'm looking for the power of the comp cam I currently have but one that has more grunt when pulling a load in the 1800-3000 rpm range. Advice or experience with these two cams would be greatly appreciated. Thank's


I think the 208 cam might be too small considering you 9.5 compression And useing this vehicle as a working truck (towing & hauling).
The 220 degree cam looks like a rough copy (or vice,versa )of the comp you have now? I see no real difference. I doubt you would either. I'd think the difference MIGHT be measurable on a dyno but not noticeable by the seat of your pants.
Have you thought about advancing the 268 cam slightly to see if you like it that way? ?
In a seperate thread StrangeRanger made a good observation that 300s had a torque platau instead of a torque curve.
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When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

3004speed
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Re: Cam choice

Post #9 by 3004speed » Fri Mar 15, 2013 2:58 am

Hey 80broncoman,
The comp cam is coming out for this rebuild.Problem with two lifters.Called Clay Smith back today and he said ideally the 264 grind would be the most versatile for the big six.Grind specs:480 lift -208@.050 and 108 lsa.He said just as you that at my compression I would need the higher duration to help bleed off some of the compression.The head has already been shaved,so I can't get that back.Whats your thoughts on going with the efi head over my current head to reduce the compression? Also thinking of ditching the clifford headers for efi manifolds.Its my belief the efi heads with the extra bosses for alignment would really be an asset.Its hard to keep them headers and clifford intake centered over the ports in the ole log head.The comp cam I have is 218@.050 110 lsa. The Clay Smith 220 @.050 108lsa.I was hoping going with the 108lsa would get me some of the low and midrange I need only while towing and the 220 duration still giving me top end I have now.
Really appreciate everyone taking time to help

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Re: Cam choice

Post #10 by nightwatchman59 » Mon Apr 08, 2013 1:03 am

No thoughts on RHOADS lifters? Variable valve timing is all the rage now, right?

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80broncoman
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Re: Cam choice

Post #11 by 80broncoman » Mon Apr 08, 2013 2:01 am

nightwatchman59 wrote:No thoughts on RHOADS lifters? Variable valve timing is all the rage now, right?


Was just discussed recently in this thread
viewtopic.php?f=2&t=69448&hilit=RHOADS+lifters
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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MechRick
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Re: Cam choice

Post #12 by MechRick » Tue Apr 09, 2013 5:27 pm

Interesting feedback on the Comp 268 Rick. I'm going to use one in my Anglia w/ a C4 / 9" w/ either 2.75 or 3.25 gearset. I hope it gives me a nice drive-in cruise night style lopey idle and still moves the 2300 lb car along the highway. At 2300# I can afford to give up some bottom end and still have lots of fun at the top of each gear. We'll see.

The 268 will lope nicely with a carb intake. Since the conversion to EFI most of the lope went away in mine. I'm hoping the power doesn't drop off too much when I switch back to a stock cam. By the way, the cam card on mine listed duration @ .050" at 219 degrees.

I've got a video of my truck accelerating to 85 mph I'll upload to youtube one of these days...it runs extremely well with great torque above 1300-1500 rpm. Pushing a 2300 lb Anglia should be a riot. Take me for a white knuckle ride, pleeeze? :)
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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