cam experts?

[blubuckaroo]

Would the advantages of a dual duration cam for a SBF be lessened by better flowing aftermarket heads?

I think I see what you mean. By my Goober Pyle reasoning, say you have a head that flows poorly with the exhaust or intake, you want a cam that would either open the valves more or faster so they can be open longer to fill and exhaust the cylinder more efficiently. If you replace that head with one with better flow capabilities, you wouldn't need to open the valves as far or as long to get the same flow. It doesn't seem that I would need as radical of a cam to do the job with good heads.

 

[TDubya]

I think I see what you mean. By my Goober Pyle reasoning, say you have a head that flows poorly with the exhaust or intake, you want a cam that would either open the valves more or faster so they can be open longer to fill and exhaust the cylinder more efficiently. If you replace that head with one with better flow capabilities, you wouldn't need to open the valves as far or as long to get the same flow. It doesn't seem that I would need as radical of a cam to do the job with good heads.

I don't know for sure, but it makes sense to me. A more radical cam or better flowing heads would make improvements on their own, but the best performance would be achieved when they are properly matched. A cam tech should be able to do that.

 

[Vintage Steel]

These guys are very helpful:
Summit Racing Tech Support
1-330-630-0240
They've helped me pick several cams and I was always satisfied (even when I bought elsewhere)

 

[blubuckaroo]

How about this cam?

E950P
Melling Select Performance
.472/.496 Lift - 214°/224° @ .050

Product Description
Fits: 1962 to 1991 289ci - 302ci - 351W*

• 280°/290° Adv. Dur.
• 112° Lobe Center
• 61° Overlap

• Idle Quality: Fair with lope
• Power Range: 2000 - 4800 RPM
• Good choice for light towing
• Recommended spring pressure 110lbs. for valve on seat; 280lbs. for valve open
• Compression: 10.3:1 or less
• Transmission: Stock auto or Manual

THIS CAM CAN BE USED IN THE 351W AND 302HO BY RE-WIRING THE DISTRIBUTOR TO FIRING ORDER: 1-5-4-2-6-3-7-8

 

[TDubya]

Sounds like a pretty agressive cam with a lot of duration to me, but I'm no expert. Would have good midrange power but might give up responsiveness. All depends on what you're looking for!

 

[broncnaz]

X2 If you have the gearing for it then it will work. I wouldnt run that cam with any OD trannys though.

 

[av bronco]

Comp cams has the worst tech. support Ive ever seen, they say they have a tech"hot line" but try to call it, it's a joke! Ive got better customer service at my local DMV. also they dont give you lift at .050 they want you do do the intake center line method which is not even as close to accurate as the "lift at .050 on intake. Jay at camshaft innovations is a FORD guy(unlike comp cams) and can help you out unlocking the true potental of your SBF.

 

[TDubya]

What is the intake centerline method? So the valve lift numbers from Comp are not at .050 lift? I'm confused.

 

[Viperwolf1]

What is the intake centerline method? So the valve lift numbers from Comp are not at .050 lift? I'm confused.

The centerline is the point of maximum lift. It's also a technique used to degree the cam, not as accurate as the .050" method because 1) it's more difficult to accurately determine where the centerline is, and 2) it can lead to errors if the lobe is not symetrical.

 

[broncnaz]

From what I've seen comp cams does give the duration at .050 as do most cam manufacturers. They also give the lobe centerline which some manufacturers dont. I remember a few years back Ford motorsports only listed durations at .004

 

[ken75ranger]

What did Crower send you for specs?

 

[73azbronco]

As an example of compcams, here is what their compquest software recommended as the second choice for my EFI, roller, 8.7cr, 351w:

XE264HR
1,500-5,500
LCA 114
Intake centerline 110
duration int: 264
duration ex 270
duration at .05 212/218

event int open/close 22btdc/62abdc
event ex open/close 73bbdc/17atdc
lift w/1.6 .512
lobe lift .321

I picked the second choice because it had 114lca, the first had 110. torque and HP were within 15.

 

[av bronco]

From what I've seen comp cams does give the duration at .050 as do most cam manufacturers. They also give the lobe centerline which some manufacturers dont. I remember a few years back Ford motorsports only listed durations at .004

They give the duration but you degree the cam with the LIFT. Comp cams gives you degrees at .006 lift which is not enough lift to determine accuracy. also if you use there method and then check the lift at .006 you will come up with two diffrent readings, Ive been waiting for a month for the reason and they wont respond to e mails, or phone calls. My theroy is a piss poor Q.C.

 

[73azbronco]

Comp cams gives you degrees at .006 lift

Thats a good point, I have a question into comp as well.

my theory is it's not that they have sucky quality, they'd be run out by every performance forum if they sucked. My theory is they do it to prevent cam by cam comparisons between companies, thereby forcing you to buy on gut versus comparison.

 

[Viperwolf1]

Thats a good point, I have a question into comp as well.

my theory is it's not that they have sucky quality, they'd be run out by every performance forum if they sucked. My theory is they do it to prevent cam by cam comparisons between companies, thereby forcing you to buy on gut versus comparison.

That sounds like a good theory. It would be easy to measure the duration at .050" if you had one of there cams though. But I'd say 98% of engine builders never use a degree wheel.

 

[blubuckaroo]

What did Crower send you for specs?

No response from Crower.

 

[av bronco]

That sounds like a good theory. It would be easy to measure the duration at .050" if you had one of there cams though. But I'd say 98% of engine builders never use a degree wheel.

The problem is I dont know what the degree wheel should read at .050, and olny the cam grinder can determine what it is. I have a reading but no refrence as to what it should be. Comp Cams is the olny manufactuer that does the .006 thing, and on a roller .006 can be +-10 degrees at crank.

 

[Viperwolf1]

The problem is I dont know what the degree wheel should read at .050, and olny the cam grinder can determine what it is. I have a reading but no refrence as to what it should be. Comp Cams is the olny manufactuer that does the .006 thing, and on a roller .006 can be +-10 degrees at crank.

I was talking about determining the duration at .050" for comparison to other cams. You should be able to find .050" lift using a dial indicator with a pretty good degree of accuracy. Note the crankshaft degree reading at that point then turn it over until it gets back down to .050" and note the degree reading again. The number of degrees between those points is the duration.

 

[av bronco]

I was talking about determining the duration at .050" for comparison to other cams. You should be able to find .050" lift using a dial indicator with a pretty good degree of accuracy. Note the crankshaft degree reading at that point then turn it over until it gets back down to .050" and note the degree reading again. The number of degrees between those points is the duration.

The duration at .050 is on the cam card and on the web sites for all the cam makers but what the card says and what the cam does is two diffrent things on a ots cam, never had a custom cam yet but thats gonna change soon.

 

[John Marinan]

Call Howards Cams. You get a real person. They custom grind the cam to fit your needs.