427 Camshaft Choice ???????

[GUMBALL]

I could use a few more opinions on camshaft specs for my current engine build. This is a difficult decision without actually testing camshafts by test driving the car.

What would YOU all consider the upper end of "streetable" and still a reliable, non-stalling, pleasure to drive around town?

Here are the engine specs:

Alum. 427 (4.25 bore)
4.25 stroke (healthy)
482 cubic inches
10.8 to 1 compression
Dual plane medium riser manifold
2.25 x 1.75 alum heads

This should be quite a torquer no matter what camshaft is chosen but H.P. could very dramatically. If I had the opportunity to drive a few dozen Cobra's with diferent setups this would be easy. Since that isn't likely, I must defer to the clubs infinite EXPERIENCE.

I would truly appreciate any thoughts.

Regards,

John

[Rick Parker]

Contact one of the camshat companies they are the most knowlegable and experienced. They all have the software packages that can help through this maze of confussion. What may be tollerable for one individual may be off the scale for another. Not to over simplify this but the entire intake and exaust
systems must be factored into the decision of which camshaft to choose. If you want to have some fun and see what a specific change will theoretically do get the Desk Top Dyno or other similar engine maping tool. Last time I checked it was in the automotive section at Barnes & Noble Books. Good luck but dont
over cam it.

Rick

[Jack21]

A few tips on selecting the right cam.

You're not a cam guru, and neither am I, so I ask the folks that make or use them. Crane & Comp cams are good at this.

If possible, use a hydraulic roller retrofit setup. I know Crane, and I think now Comp has rollers for FE motors.

Typically, the HP street cam range is 218 - 228 I, 224 - 234 E duration @ .050.

Get yourself a copy of Desktop Dyno 2000 from most any speed shop, Summit, or direct from motionperformance.com. This is the one tool you need to play these numbers games and see where you get results from. Play parts substitutions all day long. $40 - 50. You Windsor stroker guys; substitute Cleveland 4V heads on your 393 or 408 (and particularly your 427) and see what happens. It will bite you!

[Jack Zupan]

Jack21,

What do you mean when you say using 4V Cleveland heads on a stroked motor will bite you? Are you saying that is a bad idea? If so, why?

Jack

[Jack21]

Jack Z,

Sorry for the confusion. No it's certainly not a bad idea. What I meant by "It will bite you", was the difference is so astounding, and so obvious that it will bite you. e.g. not subtle differences.

Specifically, using Dyno 2000, run the numbers on a baseline 351 engine. Use a combo you'd use in your car with respect to bore, stroke, CR, intake, carb, exh, cam, valve sizes. Use the 2.02/1.60 in a typical aftermarket Windsor head. P. tq @ 4500 RPM, P. HP @ 6500 RPM. Good street motor.

Change the stroke from 3.50 to 3.85 (393), with everything else the same. P. tq & P. HP RPM drops, and gets worse as you increase the stroke to 4.0 (408), and 4.17 (427). The 2.02/1.60 valve sizes that work well on a 350 size motor is hurting you as displacement increases to 400 CI and up. Then run this exercise over again using large port canted valve 2.19/1.73 (Cleveland heads). (Dyno 2000 has specific sections for Ford, Chevy, Mopar, and other motors, so you're not building a Ford motor with Chevy parts).

In short, at 400 cubic inches, the Cleveland head vs Windsor head side by side comparison "will bite you!"

And the irony is this. You almost can't give a set of Cleveland 4V heads away. Nobody wants 'em. So let's keep our little secret on what these heads will do on stroker motors (Cleveland or Windsor), and what these 427's could do in the right hands.

[Jon Miller]

When I was searching for a cam I thought that I would do the logical thing and put all of the available FE cams on a spread sheet and try to rank them from mild to race. I included the manufacturer's comments such at "rough idle", "great bottom end", etc. I figured that it would be a simple matter to compare specs and comments and end up with just what I was looking for. When I showed my spread sheet to the race car expert at work he laughed and told me that cams are more of an art than a science. On his advice I called PAW and talked to one of their "experts" who may or may not have had a clue about what he was talking about. I guess that I'll find out when I get the motor done and fire it up the first time........

If I were to do it all over again I think that I would go to the upcoming mini-nats, find a car that has the characteristics that I want, and use the cam that that guy used.

-Jon

p.s. John, if you would like a copy of my worthless spread sheet please feel free to stop by. I'm on the corner of Lochinvar and Inverness. It's the house with no roof and a big blue dumpster in the front yard. I'll be the guy pounding nails on the roof.

[RICK LAKE]

HI JOHN RICK LAKE HERE YOU SAID YOU HAVE AN ALUM ENGINE IS IT A SHELBY MOTOR I HAVE ERA 428 ALL ALUM ENGINE F.I. SUPERCHARGED MY CAM IS VERY SMALL 510" I 533" EX HYDRO MY MOTOR IDLES AT 750RPM WITH NO SHAKE ENGINE CUBES IS 452 IN. MY CAR IS VERY STREETABLE 6 SP. RICHMOND TRANS 330 JAG REAR CHASSIC DYNO WAS 328 HP 423 TQ. WITH A FLAT POWER BAND WITHOUT SUPERCHARGER THE CAM WAS RETARDED 4 DEGREES THE CAR GETS RUBBER IN 3RD GEAR. IF THE MOTOR IS SHELBY TALK TO MIKE LEFEVERS AT MITECK # 310-538-2914 HE WAS A GREAT HELP IN BUILDING MY MOTOR THE HEAD WERE CNC NEXT YEAR I AM GETTING ROLLER ROCKERS FROM MIKE YOU MY WANT TO TALK TO PETER AT ERA ABOUT YOUR COMBINATION FOR YOUR ENGINE IS THE CAR FOR RACING,CRUISING, HIGH SPEED RUNS RUN@GUN OR WOMEN CHASER IF YOU NEED TO TALK, YOU CAN EMAIL ME AT RDCOBRA428@ AOL.COM GOODLUCK WITH THE CAM AND CAR RICK LAKE P.S. POWER IS YOUR FRIEND BUT TORQUE IS WHAT GETS YOU MOVING

[GUMBALL]

Rick, Jack21, John, Rick

Thanks for your input. The block (and everythng else) is Shelby. Using hydraulic flat tappet and roller rockers I have spent a great deal of time on the phone with Mike. Based on MY definition of streetable, he suggested a Comp cam with duration @ 275 I - 285 E and lift @ .515 I - .541 E.
He also said my current setup would easily accept 300 duration and .600 lift (with zero modifictions) and should increase H.P. by 20%.

The difficult part here is, "What is the definition of streetable"? It is different to everyone. I just want to try not to under/over spec the camshaft........ either one will be dissapointing.

To sum up:

I WILL get a copy of Desktop Dyno, give a call to the cam mfr's, and Rick, I will get ahold of you. (thanks)

Jon- I know how you felt......... what is the definition of "choppy", "racey", "radical", "fair", "mild", "srong", etc.? One needs a reference point to discern the difference.

Thanks again for your all of your input. I will advise on the outcome.

Regards,

John

[ERA#569]

Gumball, I also have a shelby stroker and went with a Lunati 300-310 Duration .560 lift Intake- .580 lift Exhaust. It sounds mean & idles at 950@ 12"of vacuum. I did have to drill a 1/8 holes in the primary throttle blades for it to get enough air at idle. I have drove in a couple with less cam & more cam , but thought this would make use of the extra cubes and still be good street cam.If you dont want to adjust valves every year I would stay with hydr- roller as Mike suggested.I have not driven #569 yet to tell you If I made the correct choice. I have been breaking in the engine and had to get a new carb. Should drive it for the first time down my drive- way this week ! Then down the street !Let me know what cam you pick. Scott

[GUMBALL]

Scott,

Thanks for the info. Sounds like a great setup you have. Let me know how it works out on the street. Hell, I have another 5-months before I can do that.

I spoke with Mike at Shelby again and have finally made a decision!!!!!!!!

He had recently dyno'd the Edelbrock Performer RPM in one of his 4.25 strokers with great success. H.P. was around 540 and Torque came out around 560, AND, was able to acheive idle around 950 RPM................. very streetable in his view. All this with the weight of a small block! Can't wait to see how it performs. (fingers crossed)

The cam specs are 296 Duration and .572 Lift.

Thanks to all of you for your help. I truly appreciate your input.

Regards,

John