Cam Sizing

[SikNingStang]

I have a 1994 Mustang GT Conv. it has 110,000 miles on the motor and no known problems and has been pretty much babied all the time cept on certain weekends... I high doubt there is any serious engine wear...

I'm looking to install a cam on this puppy very soon but what size would be safe for my car yet still give it that intimidating lope I want? All components are stock but I will be replacing all gaskets, timing chain and the lifters when swapping cams. I will also be putting my long tubes on with the cam... I'm not sure what size will be the biggest I can get yet still be relatively safe on my motor. This car will only be driven on weekends b/c I got me a gas sipper during the week so it won't have a daily commute getting put on it...

Any suggestions will be much appreciated... Thanks in Advance...

Jon

[SVTcobra306]

Crane 2031 has a healthy lope, but is a bit much for stock heads. If you ran a 2031 with 1.6 rockers it'd probably be OK, but a cam is usually overkill on a stock head/intake motor. The heads and intake are more of a bottleneck than the cam, that's why usually the intake gets changed first, then heads and cam while the motor is apart...

[SikNingStang]

Yea I was just looking into that. I think I'm also gonna get an Edelbrock Performer heads and intake... It says the Edelbrock heads can handle up to .575" lift... How much lift would be safe with stock pistons? I was also looking at the GT-40 upper and lower intake but I haven't made up my mind yet. I wanna make sure I search out my best options. Thanks for the advice.

[SkylineUSA]

.500 lift is still a pretty good lift. I am going with .550 for my build, but normally if you go over .500, and you have a fairly wide duration, you better check your valve clearance. I'll post ya a little cam chart when I get home tonight.

[351wStang]

You runnin a f303 cam Tony? If so where did you get the 1.72 rr's for windsor heads?

[SikNingStang]

Thanks Skyline that'll be helpful. Oh and 1 more thing... how do I figure out if my car needs a roller/flat tappet/solid cam?

Thanks
Jon

[SkylineUSA]

Originally Posted by SikNingStang

Thanks Skyline that'll be helpful. Oh and 1 more thing... how do I figure out if my car needs a roller/flat tappet/solid cam?

Thanks
Jon

Jon,

Look at your lifters, that will tell ya.

Not really a chart, but you get the point

Advancing the cam gear opens a valve earlier, and closes it sooner... retarding the cam gear, opens the valve later, and closes it later... since all you've done is moved a fixed event.

Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier.

Retarding Intake and Exhaust : This will increase the cars top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.

Advance Exhaust Only : This will help the cars top end, and it reduces overlap.

Retard Exhaust only : This will help the cars mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once.

Advance Intake only : This will increase overlap and helps the cars bottom end and mid range power. This mod will bring the turbo on all at once.

The lift has a dramatic effect on low R.P.M. performance, but has a lesser effect at higher R.P.M.s.

Duration has the opposite effect of lift. The longer the duration, the more the R.P.M. horsepower will be boosted, but it is at the expense of lower R.P.M. horsepower.

As we all know, it's a bunch of trade offs. What one tuner might think is a good trade off, another will think its a bad trade off. That is when the debates will start.


David,

With the 205s, I am using 1.72 Scorpions 7/16 stud RRs

[SikNingStang]

^Wow, that is SOOOO much more information than I ever expected to get... Thanks a lot Skyline... I have no clue on how to advance/retard that stuff but now I know what the affect will be... but informing me about duration and lift will help me make a much better decision on the kind of cam I am looking for... Thanks A LOT...

Jon

[SkylineUSA]

No probs, I like cam talk.

[SVTcobra306]

FYI all 5.0 HO motors after 1985 were hydraulic rollercam motors.

You can run a Crane 2031, Steeda #19, Crower 15511, or a custom cam by Ed Curtis at FTI, and your computer will get along OK. AFM may make a cam for our bastard child cars too, but I don't think so. You'd have to call them.