Now that's a Cam

1Trkpony · #1 (**permalink**) 02-18-2005, 05:13 PM

In an effort to get my recently aquired ERA541 to run tip top I have been having fun tuning the carb, etc. The car has an alloy shelby built 427 in it with their MR heads, intake, etc.

The original owner swapped the shelby sourced Holley 3310 vacuum secondary for a 600 CFM edelbrock to get it to run better. I thought best to go back to the Holley and did a proform main body upgrade at the same time. I have been having a heck of time getting the car to idle well and have good throttle response. The engine wanted a ton on initial advance (like 20+ deg) and would not idle much below about 1200 rpm with 6-7 in/Hg of vacuum. Even then the engine would stumble below 2500 rpm. But at 3000+ rpm it would pull like nothing I ever had driven, scary fast.

So I decided to call Shelby and get the specs on my engine. It took a few times to get the right guy but I finally got through this week and got my info. My engine has a comp cams 33-242-5 hydraulic cam in it. It is a 0.611/0.611" lift, with 260/260 @0.050" duration!!! No wonder this thing idles like a pro-stocker. On Comp's web site they list this cam a "Drag Race Only", opperating range of 4500-6800rpm. All I can say is wow. The guy I talked to at Shelby was a little surprised they put that big of a cam in (it was built in '99 before he got there).

So my dilemma is what to do? I do not intend to race the car, just street drive with the potential occational open track. I probably should change the cam out as I don't think I am ever going to tune it to be very street friendly. I have a wide ratio top loader with a 3.31 rear ratio So what cams do you guys recommend? I was thinking something in the 235 range with a lift of ~0.550" for a good balance of low end torque and top end HP as well as easier on the valve springs.

Hope to be able to swap the cam with the engine in the car. I will probably have to pull the radiator though. I think I want to stay with hydraulic as that is what is in there now and the block is set up for it. If anyone has any good cam recomendations I would very much appreciate it!

Excaliber · #2 (**permalink**) 02-18-2005, 05:43 PM

I'm running those 3:31 gears with a top loader close ratio. I to had a BIG cam with high compression, difficult to tune to say the least. Ran like stink at the drag strip, 11.90 and I wasn't even trying that hard! Hell on the street though.

So I looked on Gessfords web site to see what HE recommends. What kind of typical cam does George sell, I asked myself. I wanted a cam that would work in the 2500 to 6000 range for a more "streetable" engine. He recommened solid flat tappet cam, just like the one he has on his web site! Also geting the matching springs for less less pressure. I was running a soild roller cam before.

I also changed my carbs from full blown race center squirters to a more mild vacuum secondary Holleys.

Of course you will probably want to stay with hydraulic, but your onto something big. Most motors are just built "to much". I like to cruise! You might give George a call.

ERA Chas · #3 (**permalink**) 02-18-2005, 06:00 PM

1Trk,
My response to you is on "shop talk". The forum changed while I was writing it!!!
Hope you look there.

CJ428CJ · #4 (**permalink**) 02-18-2005, 07:32 PM

1Trk,

I can't recommend a cam for you but I can tell you the cam will come out of an ERA without pulling the motor. You'll need to remove the radiator and you also need to loosen the motor mounts and lift the front of the engine just a bit with a floor jack. As your lifting the motor with a floor jack, keep an eye on side pipes where they exit the body. You may have to loosen your headers to keep your side pipes from hitting the body at the side pipe exits.

Chris

Cracker · #5 (**permalink**) 02-18-2005, 07:46 PM

I wouldn't change it.

I had a crower 16332 w/ 260 @ .50 and loved it! I then had a second motor with a milder hydraulic cam and comparitively it was blah, blah and more blah - never again. In fact, when my side oiler was rebuilt we used a .691 lift solid roller (Comp Cams) and it idles at 800 rpm's and purs like a kitten and roars like a lion (7600 rpm's!).

With a hydraulic lifter set up your springs can't be to extreme because if they were your lifters would not pump up and valve float would be induced. For what it's worth it seems like something could be done to get the car to run better - mine was fine with a very similar set up. Best wishes.

One more thing - throw that holley as far as you can and buy a Mighty demon 825 cfm from Barry Grant. It's a mechanical secondary unit that runs circles around the holley I replaced it with. It's more adjustable (four corner) than the holley but I don't know how it compares to the Proform.

1Trkpony · #6 (**permalink**) 02-18-2005, 08:30 PM

I did contact George (email first) and will be talking with him next week. He was the first one I thought of too. BTW The engine is 10:1 compression ratio.

Agree with the carb comments with the present combo. If I was to keep it I would most likely go with a mechanical double pumper carb with as big as I could get like the demon. I would have never tried to make the Holley 750 vacuum secondary work if I knew the cam spec before hand.

CJ428CJ thanks for the heads up on getting the cam out. It sounds doable, though a bit of a pain.

Cracker on your cam, I am surprised it is so streetable. Maybe being a roller makes it more civilized. Either way sounds like you have a mighty beast. Maybe I am wierd but I doubt a 2500# car with a healthy 427 would every be blah :-)

Again I would be interested in hydraulic cams each of you has used and how they worked out.

Thanks in advance.
Russ

RICK LAKE · #7 (**permalink**) 02-19-2005, 07:22 AM

1trkpony Russ do yourself a favor, Check with George, See what he says, If you like solids and the adjustments than go that way. I would get the dyno 2000 or dyno sim and build the motor on there. See what you are looking for. HP or Tork motor. Match the heads, compression, exhaust flow, rpm range of motor to the cam.I have had .700" cams in a hemi with the same cubes and it idles like SH*T. It barely idles at 1000 rpm. It wouldn't idle at 800.Look at the crane 533-566 cam and degree it. Has I lope idle, great midrange pull and goes to 6k rpm. Hydro lifter keep from the R&R of valve covers every month. The motor would make 430hp and about the same in tork. The drivablitity would be good and maybe 12-14 mpg. I have 501-533 the next one down, for a blower motor but didn't get it to run right. Motor makes 366hp and 468tork on the dyno. Add an Alumium flywheel to your car. The motor rev will go faster and quicker. I run 12.5 in the 1/4 mile with 3.31 gears. Bigger is not always better. Make sure you have a good oiling system for your car. You have a private e-mail Russ Rick Lake

bobt427 · #8 (**permalink**) 02-19-2005, 03:15 PM

I must have the same cam that Rick has. Its a Crane cam part #343941 533 lift intake & 563 exhaust 272&284 duration. I have it in 390 4 speed wide ratio toploader 3.27 ratio rear end. The cam has a nice lope,but very streetable . On the dyno it pulled strong to 5200 rpm.

BB427 · #9 (**permalink**) 02-19-2005, 08:55 PM

I have a Comp solid 306. It is .651 lift in/ex and 260 @..050 duration. It is too much cam for cruising around but it sounds awesome and runs great if you buzz the motor. What the hell, nothing about this car is practical I might as well enjoy it.

Brent

1Trkpony · #10 (**permalink**) 02-20-2005, 09:32 AM

Thanks for the suggestions. In looking at cams there are a lot of solid lifter cams for FEs. I have not looked at solids due to the fact my shelby block is already set up for hydraulic. But I was thinking they would be okay. Can I run a solid without oiling system mods? I already have the adjustable rocker arms.

Excaliber · #11 (**permalink**) 02-20-2005, 10:37 AM

On the FE hydraulic blocks a "restrictor" can be added or removed quite easily to accomadate soilds or hydraulics. I wonder if the Shelby blocks have the same feature? If so, piece of cake!

George as Gessford made an interesting comment once. He said he thinks people SHOULD have solids because it "keeps them in touch" with their motor, gives them a reason to be under the hood on occasion and become one with your motor.

Is that like saying, real men run solids?

RICK LAKE · #12 (**permalink**) 02-20-2005, 02:48 PM

Excaliber I agree with George about being in touch with your engine, But wheren't you the one who lost a motor? You are not the only to be weak on maintaining a solid motor. I was the same way with the Hemi and having to adjust the rockers after every run. Somethings we said the hell with it and broke a rocker. What a pain that was. With a hydro cam being setup right with the lifter lash, there is not any adjustments needed but once a year. With a small cam, .550" lift you can put a vaccum gauge on the motor and see if any of the intake valve are out of adjustment. Unless you have real DEEP pockets for breaking FE motors, I would rather have a little less power and a little more time to work on the suspension. A great handling car can draft a more powerful car all day long. I think what George is saying is the motors he builds with solid cams and get proper maintance will last A long time. Neil and George build endurance motors that run&run. They may not have the power that some others claim but I have not see a Gessford motor's guts laying on the ground yet at Run&Gun. This can not be said about others. Joe B from Cali builds the same kind of motor for over 37 years and have the same kind of results with motors going a whole season of racing and only needing a freshen over the winter. Mostly bearings for the FE rods. I still stay with the bigger is not allways better. I will let you know when motor#2 is built and running. 484-489 cid with the small roller cam from crane 587-607. A 650" cam is about the right size for this motor but not what I want from this motor. Hydro lifter, roller with some oiling tricks should work great. Rick Lake

SCOBRAC · #13 (**permalink**) 02-24-2005, 04:12 PM

you might try two 750 holley's

Excaliber · #14 (**permalink**) 02-24-2005, 04:29 PM

I suspect a rocker arm shaft broke on my motor leading to a sudden and massive valve tappet clearance on the last rocker\valve. Thus, pounding the hell out of one of my roller lifters.

I'm going back with flat tappet solids, but I could see running hydraulic if performance wasn't the BIG issue. And on my new build it is not.

Very lucky I didn't grenade that high dollar side oiler block!

FUNFER2 · #15 (**permalink**) 02-24-2005, 05:50 PM

Russ, I had Comp Cams custom grind me a cam. Solid flat tappet.
290/298 .015 - Duration 252/260 @ 106 center - lobe seperation 110. For me, this is a perfect cam. Lot's of rump at idle & great responce. Will idle all day @ 900 rpm. It was dynoed at 503 hp. I also have a chassis dyno run sheet. If you want the part & grind numbers, they are now selling this cam. Email me if you wish.
Thanks,
Kev

1Trkpony · #16 (**permalink**) 02-24-2005, 08:04 PM

Thanks everyone for the assistance and advice, but I wimped out and got a milder cam. I got a Comp cams dual pattern with 0.565" lift and 230/236 duration at 0.050" hydraulic cam. I know a lot of you will say I went too mild, but for now it seems to fit my requirements well. It should really change the engine's characteristics completely and give me a nice balance that I am looking for. Hope to swap it out this weekend and try it out.



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