looking at cams

67chrrybucket

Well-known member
I was shopping on the old summit racing for a cam for my 300 i was most interested in the comp 252 grind for my street comet but looking at the rpm range on this cam is 4500 about all i need out of this 300 or should i step up to the 260 grind? Also i noticed a howard cams cam that was right in the middle of those two but had a 108 lobe center im going to guess that would be too rough an idle for a street machine?
 
67chrrybucket":3lwwx363 said:
I was shopping on the old summit racing for a cam for my 300 i was most interested in the comp 252 grind for my street comet but looking at the rpm range on this cam is 4500 about all i need out of this 300 or should i step up to the 260 grind? Also i noticed a howard cams cam that was right in the middle of those two but had a 108 lobe center im going to guess that would be too rough an idle for a street machine?

If your wanting a noticeable power increase you will need more than that 252 cam. The 252 really isn't all that different from the stock cam. in a smaller lighter vehicle you could stand to have ever more than the 260 you are thinking about.
I'd think you wern't going to swap in a 300 just because you have one laying about......
compression , trans (which torque converter if auto), which intake & carb, useage all come into play.
 

THE FRENCHTOWN FLYER

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80broncoman":1uwk1ifg said:
If your wanting a noticeable power increase you will need more than that 252 cam. The 252 really isn't all that different from the stock cam. in a smaller lighter vehicle you could stand to have ever more than the 260 you are thinking about.
I'd think you wern't going to swap in a 300 just because you have one laying about......
compression , trans (which torque converter if auto), which intake & carb, useage all come into play.
I agree. I'm using a CC 268 in my Anglia build, similar to the one in my Willys coupe, which runs "nicely" with that much cam.
 

67chrrybucket

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Well it will be a in a lightweight Comet with a 4 speed toploader wide ratio mostly street driven with an occasional 1/4 mile runs so broncoman i just got one in trade but its what i wanted to do since i got the Comet so i guess i was thinking too small so i should be thinking 268? I just didnt want to overcam or float valves,as far as intake and carb i was thinking offy c and a edelbrock carb,and a 3.25 RAR
 
67chrrybucket":3kuxcxp2 said:
Well it will be a in a lightweight Comet with a 4 speed toploader wide ratio mostly street driven with an occasional 1/4 mile runs so broncoman i just got one in trade but its what i wanted to do since i got the Comet so i guess i was thinking too small so i should be thinking 268? I just didnt want to overcam or float valves,as far as intake and carb i was thinking offy c and a edelbrock carb,and a 3.25 RAR

Yes defiantly get you a 268 cam. it would be my choice for sure. If the cam you got is a NEW comp cam Comp might just trade you out. We did that at Crane years ago to keep parts out of the flea markets.
 

67chrrybucket

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I have not bought cam yet but im glad i posted this question first i like the idea of a bigger can i was just worried about over caming but since i was planning on a 200 it makes sense a bigger cam would be neaded
 

MechRick

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The Comp 268 is a nice grind. Since I've recently swapped back to the stock cam in mine, I can tell you that anything milder and you might as well run a stock grind (mine was supplied by Melling). To quote Dave Williams of Fordnatics fame, "cheap is a quality overcoming many faults".

The 268 isn't dramatically thirstier, either, although the bump in dynamic compression may require top shelf octane.

The kicker is, if you run a carb head and an Offy C intake you are going to get a nice, rumpity lope at idle.
 

67chrrybucket

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I like a nice lope on the idle as long as it doesnt affect performance,so anybody that answered this post that has a comp cam do i run any advance when degreeing or straight up? I guess im going with a CC268 grind :nod:
 

THE FRENCHTOWN FLYER

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One other suggestion I would like to make is to use a higher stall converter - that will really wake up your lightweight ride. In my '33 coupe I use a ten inch 351 Cobra Jet factory converter, which has a rated stall speed of 2500 RPM. (Interestingly, behind my 305 engine it also stalls at 2500 RPM which tells you that at that speed the 305 makes about the same torque as a 351 CJ.) Likewise, my kids' 240 mildly built Anglia has a 4000 stall 10 inch converter and it is very tractible on the street and runs 14s at the strip.

I remember when I first got involved with using torque converters for performance builds. I argued with my mentor that my 300 six should have a tight, low stall converter because of the low RPM qualities of our six. Unconvinced he told me, "Go ahead and use a tight one. You aren't going to know how much a high stall converter will help you until you try a tight one."

Of course, fuel consumption was of no concern to me - just going fast.
 

Baron Von Ottomatic

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I think Comp sells a pretty hot solid lifter cam for the 300, something like 220 degrees @.050 on 108 lobe centers. As long as you don't mind adjusting the valves every now and again it ought to run nice in something like a Comet.
 
Baron Von Ottomatic":1qa3b5rm said:
I think Comp sells a pretty hot solid lifter cam for the 300, something like 220 degrees @.050 on 108 lobe centers. As long as you don't mind adjusting the valves every now and again it ought to run nice in something like a Comet.

if you deduct 6-8 degrees of duration @ .050 for the lash in a solid a 220 solid cam is smaller than the 268 hyd cam.
 

Baron Von Ottomatic

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Hmmm, I would have thought that cam duration measured at .050 - after the lash is played out and the valve is off the seat - would be what it is. You know, like a solid lifter cam with 280 advertised duration but 220 degrees @ .050 vs. a hydraulic cam with 268 advertised that shows 218 degrees at .050. But apparently I would have thought wrong.
 

67chrrybucket

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Okay so i called Comp cams and had them spec me out a cam with a basically stock 300 with the offy c intake 4 barrel carb and the efi exh manifolds this is the cam he sent me i wanted to get opinions fromt those who have already comented Comp cams 224/230 duration @ .050 lift .516/.528 108+4 lobe centers valve open 8/47 closed 36/3 i think this looks a bit on the big and choppey side but those who understand cams better than i can please chime in
 

MechRick

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That's pretty aggressive. I would hesitate putting that one into a truck, but I think it would work fine in a lightweight car.

If you use that one, pay careful attention to spring pressure and coil bind. It will like to rev.

Also, whenever I see that much duration ground on 108 lobe centers, I look at the advertised duration overlap number. If it is more than 55-60 degrees, then a full length header would produce much more power than cast iron exhausts. The overlap allows scavenging, what David Vizard calls the 5th cycle in a four-stroke engine.

http://www.popularhotrodding.com/engine ... ewall.html

If you want to run EFI exhausts, wider lobe separation angles will reduce the overlap.
 

67chrrybucket

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Will that lose a lot of low end torque going that aggressive? I was going to use springs lifters retainers lock and rockers from comp if i go with this cam
 

MechRick

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It's a hot street grind. The split duration numbers are for low flowing exhaust ports (not really the case with the big six). But the tight lobe separation usually mean headers. You will usually see split durations on street cams with much wider lobe center angles (112+). I would expect to see specs like this on a cam for a 5.0L.

The torque will come in strong after about 1500 rpm, which won't be a problem in a light car.
 

67chrrybucket

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In your guys opinion what would the drivability of this cam be im sure its going to have a very lumpy idle, mechrick i also wanted to add the advertised duration was 278/280 and at .050 it was 224/230 so its within the 55-60 you were describing
 
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