Camshaft Profile any good for street?
 

Hello Cobra Folks.

I will be building an engine for my next project over the coming months and have been doing some work with desktop dyno. Thanks Butcher for your pages.... great.

Now during my trawls of the web I found some cam files for loads of comp cams.

One of them was the 35-324-8 (their part number) but it is not on any of the pages of their online catalogue. So I don't know what this cam would work like on the street.

Does anyone in here have any idea about this particular cam and weather or not it would be ideal for my motor. (351w)

The figures look great on Desktop Dyno but I was wondering if it would be OK to drive in Traffic. We get lots of that around Leeds UK which is where I live.

My ideal car would accellarate like a rocket and scare the s**t out of me and my passengers. However would need to tick over reasonably because of the aforementioned traffic problems.

Regards
Vince Gledhill
Leeds UK

You might want to run a search on cams. About half of the guys have 351's so I'm am sure someone can give you advice on cams.

For a street motor that will see a lot of stop-and-go traffic, as well as highway cruising, you want to keep the intake duration in the 216 - 224 range. Dual pattern cams can run the exhaust duration 8 - 10 degrees more.

CompCams has a single pattern retrofit hydraulic roller cam for the 351W that specs out at 224/224, .533/.533 (which is what I'm running) which idles at around 850RPM with a nice rumpeta-rumpeta lope, pulls 15" - 16" vacuum at idle (which is very good), and is well mannered in Washington DC traffic. It pulls like a diesel from about 1100 RPM, winds like a mutha from about 2800 RPM up, and gets me about 17 MPG highway crusing in 5th. Also using CompCams ProMagnum steel roller rocker arms for street use. Have 11,000 miles on motor with no problems, good reliability, and great performance.

This is the information from Comp Cams

Part Number 35-324-8
Engine 1969-present Ford
351ci,
Windsor,
8cyl.
Grind Number FW XE270HR-12
Description

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Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.544 0.544
Duration At 0.006 Tappet Lift 270 276

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Valve Timing At 0.006
Open Close
Intake 27 63
Exhaust 74 22

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These Specs Are For The Cam Installed At 108 Intake CL
Intake Exhaust
Duration At 0.05 218 224
Lobe Lift 0.32 0.32
Lobe Separation 112

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Recommended Valve Springs 986-16

Would this cam be any good for my requirements?

Vince, the XE270HR is NOT the cam for your 351W. See for yourself at www.compcams.com. It is for a 302 motor originally equipped with hydraulic rollers, EFI, and uses 1.7:1 rocker arms, and is listed in the 298 - 302 engine section.

Look in the 351W section for retrofit hydraulic roller cams for engines not originally equipped with hydraulic rollers. The cam I'm using is the 284HR, PN 35-442-8. It's a 224/224. There's a slightly milder version just above it at 215/215. One of these will work on your carbureted 351W.

Brilliant.

Thanks for the info Jack. I've just put the cam profile you recommended into desktop dyno and it doesn't really change the figures that I had chosen.

What does the car drive like on the street? I can put up with a little "tetchie" idle if I have to in order to get my ultimate driving machine. But couldnt' do with anything that I would not be able to use at all in traffic.

Thanks for your help. Now that's why I couldn't find it in the catalogue. I wasn't looking in the right place. It was there.

Regards
Vince Gledhill
Leeds UK.

Vince,

The 351W with this cam is great on the street. It is a daily driver, rain or shine, hot or cold. I do tend to be a bit conservative when configuring an engine because I know how I'll drive it when finished. Can't imagine daily traffic in Leeds England being any worse than daily traffic here in DC. 0 - 20 MPH stuck at the bridge. 20 - 35 MPH in-town. But even cruising on the Interstate at 80 - 85 MPH, that's still only 2600 - 2800 RPM in 5th. And no downshifting for passing.

Engine is well mannered, owing possibly to the unusually high idle vacuum these hydraulic rollers have. The engine does change its personality when the tach needle hits 3000 RPM, and the carb secondaries open up. You'd swear that the car has solid rocket boosters strapped to the sides.

That being said, I'd consider this cam the upper limit in a streetable street cam for a properly configured engine. The 215/215 might even be a better choice for a mostly in-town driving cam.

You're using Dyno 2000, so don't let peak numbers sway you into using too much cam or carb. Look at the area on the curve where you'll be driving the car, 2000 - 4000 RPM, and do your side by side comparisons.

I'm using TFS Twisted Wedge heads w/ 2.02/1.60 valves. CR is 9.75:1 and runs on 92 - 93 octane pump gas. Intake is Edelbrock Performer RPM. Carb is 700 Holley double pumper.

Once you get more than about 225 degrees of duration on the intake side @.050" lift, the motor starts to lose bottom end torque pretty severely. Cobras are light and have plenty of gear, which helps get the motor past those first few thousand rpm's which become a total bog. I enjoy it when the motor has the grunt from the moment I stomp the loud pedal (small cam), instead of waiting an eternity to get to 3500 rpm when the motor will start working right (big duration cam). If you only drive on the track, disreguard what I just said, it applies to real world hipo street motors, driven on the street.

mr fixit is correct about cams over 225 @.50,i have a cam with 248@.050 in my 347 and it dosent wake up until 3800rpm

Thanks guys.

That has made me wonder about all the choices I've made and put into desktop dyno. I've started a new thread asking the question about desktop dyno figures so that anyone not already viewing this thread, but knows about such stuff can voice their opinions also.

Regards
Vince Gledhill
Limey from Leeds UK