Cam quest

[sparks]

I am thinkin about pepin' up the engine alttle. My current cam specs are
-duration of 292in &300ex...Valve lift in. is .528 &.533 ex. @ 1.76 RR(dont no what the means) Valves are2.25/1.75. Could i go w/a slightly larger cam w/o changing springs and other valve train componants ? I am swaping out my old 4160 carb for a new demon w/o choke. Engine is a SA 66' 427 so.w/10.1 pistons and a 4.125 stroke. Maybe a nice custom cam from KC would help...
I figured some manufacters mite just say ,"go ahead,it should be ok" Where as someone here mite have done this allready and it worked out fine.

[sparks]

WOW, The silent treatment . I didnt think I had this many enemies. Remember its the car's not beliefs !

[Tommy]

There may be a lot of folks like me who don't consider themselves cam experts who should be offering advice. When I needed a cam, I just called my supplier (Comp Cams) and told them about my car and the engine I was building. They suggested the cam and I've been very happy with it.

[undy]

Call Keith about a hydraulic roller for it. You'll have to check on spring compatibility though. Depending what you're looking for I'd target around 240/250 duration @ 0.050 and 0.630 to 0.650 on the lift. You didn't say what intake you're running or if the heads are stock/aluminum/CNC'd. This will be very important in the equation. The heads are the FE's greatest HP bottleneck. Unless everything's well matched you could actually lose useable horsepower in the swap.

BTW.. the hydraulic roller cam swap will run you $1000+ (lifters, cam and push rods). The good thing about it is that with today's zinc additive deficient oils it makes wiped cams a thing of the past.

Dave

[sparks]

I have aluminum heads and intake . Performer-rpm intake and ported al. heads.Both (edelbroc)gonna b changin my H4160 to a more eff. carb/no choke. No hydrolic lifters in this baby. It does have roller rockers .

[289ERAkit]

I receive two totally different answers when I asked for Cam help. One was from the 23 year old kid at Comp Cams, the other from a 70 year old machinist, drag race engine, oval track, high performance boat engine builder.

Like I said....two completely different answers.

Miller Auto and Machine Haverhill MA

Phil Miller

[sparks]

Checkin with bill at SA to double check on the cam specs , but the guy at demon thought my duration seemed a little much. Durration ? This is all so confusing.

[undy]

Originally Posted by sparks

Checkin with bill at SA to double check on the cam specs , but the guy at demon thought my duration seemed a little much. Durration ? This is all so confusing.

It's not only how deep your valve can go but how long you can keep it there too..

If you're bound and determined to run a flat tappet cam ensure you remove your inner springs for break-in. Your cam lobes going away are a real and present danger at break-in .... and past break-in for that matter. The major engine builders are even plagued with this problem, hence the hydraulic/mechanical roller.

[sparks]

Here are the actual cam specs. 427so stroked to 462....Cam specs are
Dur @ .020 in.=292 ex=300
Dur @ .050 in.=242 ex=251
lobe lift in=300 ex=303
Valve lift in.=528 ex=533 @ 1.76 RR Lobe seperation is 108

Seat pressure 130.140
open pressure330.340

Hope it clears up a thing or 2...

[undy]

Your duration looks like it's right in the ballpark where it should be. A little more lift might help, around the 0.600" range for an semi-agressive street/strip mechanical flat tappet. If your cam's been around a few years I think you'll find the newer grinds to your liking too. Lift and valve load are the determining factors for your springs. Cam tech for whom ever can advise accordingly. Keith could probably recommend a specific manufacturer and grind targeting your existing combo and what your looking for.

[Dwight]

I called Keith Craft


Dwight

[sparks]

I will probably just get rid of my old 4160 w/choke and get a new Mdemon w/1" spacer to clean up flow and do my new pipes some justice.Thanks for input...

[olddog]

As someone else said the durration seems right and the lift is on the mild side. I cannot recommend swapping in more lift, without pulling the engine, so everything can be propperly measured. There is piston to valve clearance, sping coil binding, pushrod rubbing intake, and more things that need to be checked. It could be done in the car, but unless you have a good back and don't mind ending up with a bad back, I wouldn't do it.

Unless the heads were flow tested, you really have no idea what the improvement will be with more lift. You will most likely get a little more flow, but it may not be much more depending on the heads.

I never heard of higher ratio rockers for a FE, but if they exist, this would be a simple way to get more valve lift and slightly more affective durration at the valve.

I would bet there is more Hp to be gained in a good set of heads than a cam swap, unless you already have a good set of ported heads.

I guess if I were thinking of going down this road, I would pop a set of valve springs off and measure how far the valves can open with the piston at TDC. Then talk with an expert before deciding how much lift and durration the engine can handle.

[sparks]

Thanks for all the info. I think for now I will just change carb & pipes. When something major happens ,then I will have KC do something for me...

[RICK LAKE]

Sparks What are you looking for from the motor?? More torque and HP, Nasty loping idle, 300' of smoking tires, Gas mileage, drivibility, or cruising?? We need some more info than what you have given. To start with, your motor is bigger than a 427, so the camshaft for a 427 will seam small for an extra 40 cubic inches you added to the motor. If you want a smooth idle and a ton of low end power(TORQUE) a cam with a 580" on the intake and .590" on the exhaust with a 112 LSA will give you a stump pulling monster. What gears in the rearend do you have? what trans ratios are in the trans. This will all effect how the motor runs and the car drives. With the motor being a small stroker, the rpm limit would be 6,500 rpms, with a 6,700 MAX limit for long life of the motor. The other issue is the valve springs, how weak or strong are they?? 330 at total lift is a little weak for a 600" lift camshaft, what rockers are you running?? They need to be matched to the camshaft profile to get max power out of cam. I am running a hydro roller 587"-607" crane with 482 cubes. 10.5 compression motor puts out 500/500 HP and torque. I have work done to the heads, porting and run beehive springs. The only down side is a small surge at 5,800 rpms from the valve springs. Motor will run right up to 6,500 without any problems. Send some more info on this and call KCR for their camshaft ideas. He will ask the same things about size, compression, intake manifold, carb size, head work. The biggest power killer in your car is the side pipes with all the back pressure they have unless you are running a race pipe. 1-2 psi of back pressure is the idea number for max HP and Torque. Rick L.

[sparks]

Drivibility and reliability is probably the key. I have a 3:73 rear/tko trans. I am more of a get to 100 quick guy w/ alot of tire smoke. I will be putting on some 3" SS pipes.

[Dwight]

You can get Keith to do his magic on your Edelbrock heads and sell you a cam to match the heads and lifters. This way you can order what you want. A Cobra that will get to a 100 with 3.73 gears.

Dwight