Help With The Right Cam Selection

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krondo.wg

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I've been tearing apart my 73' 340 Duster, and now it's come time to put her back together. I'm not to familiar with the way camshafts work, but I know it's one of the most important parts in the motor.

I've been looking at several companies like Crane, CompCams, Edelbrock, Lunati, and Mopar Perf but I don't really know what the heck I'm looking for. I've had people tell me to look for high valve lifts, or durations, lobe-center angles, but they all look good to me.

Basically, I'd like to get some input from you guys out there with 340's or those of you who are familiar with cams.

I have no preference in brands, but here are a few things that might help you. I've never been to a drag race, and probably won't, but hey, if it's a performer, then maybe. It will be a daily driver. I'll buy the proper rear end, stall, and transmission as soon as possible, but I'm doing the topend first.


Really, to sum it all up, I want that nasty, throaty, lopey idle... that's all. What ever I have to do I'll do it. That idle is key to me, oh and longevity is kinda important :)

Any suggestions you guys have would be greatly appreciated.


*Update* Nevermind, looks like a crate engine this go around might be a more viable choice. :)
 
mopar performance book for like 30 $ read up on what you what .best info on the market (my opinion) stay in the hdy end of cam if your going to cruise sat . personally i like purple shaft . there are so many choices out there it's crazy who no's mopar better than mopar . just food for thought good luck
 
Check out Lunati's voodoo line of cams,i've used 3 different cam #'s in the past 3 seasons and have been very happy with them...Mopar cams are old school and should be left on the shelf...
 
What about comp cams Thumpr line wicked idle and perform not too bad?
 
Actually, to have any chance of successfully choosing the proper cam, you should know the rest of your combination first. What work has been done to the engine, final compression ratio, stall speed of your torque converter, rear gear ratio selection, etc.
That nasty, throaty, lopey idle is easy to aceive, but if the right combination isn't there to support the cam selection, it will be a dog to drive.
On the street, torque is basically king of the hill, and your cam selection can either benefit your low end torque, or put the usable RPM range so high that your car becomes a chore to get off the line. Build torque in to your engine, and make horsepower with the heads. Nothing beats a well thought out, well balanced combination of the right parts.
Good luck.
 
The lopey sound you're looking for is a result of intake tract reversion which results from excessive overlap (time when both the intake and exhaust valves are open). The only way to achieve this is with a long-duration cam, which are designed to give lots of top-end torque and power. Here's the catch though; if your car is going to be driven on the street any appreciable amount, it will become a pain in the *** to have a lumpy cam like that. You will need a high-stall converter if you have an auto transmission, and most likely some low (numerically high) rear-end gears. The only way I see out of this is with Comp's "Thumpr" line of cams which are designed to give the lopey sound without sacrificing too much low-end torque, which is what a street-driven car needs in order to be practical, reliable, and easy to drive. If it was my car, I'd go with a cam that has somewhat mild duration (how long your valves are left open, measured in degrees) but high lift (how far the valves are actually opened, measured in thousandths of inches). Mopar Performance cams don't really have that design and are pretty dated compared to more modern designs such as Comp's Xtreme Energy, Lunati's VooDoo and Hughes Engines (which are probably some of the best Mopar cams out there, as Hughes is a Mopar-specific engine builder). If I was you I'd call up one of these companies and tell them what you're looking for and what you have; they'd probably give you the best advice on a cam choice.
 
Call Jimmy at Racer Brown. (410) 866-7660. Tell him exactly what you have, exactly what you want to do, and if they don't have the perfect cam for your application they can cut it for you. Jimmy has been one of the top MOPAR guys in town since I was a teenager. Don at FBO had this to say about Jimmy: "Racer Brown died several years ago but his right hand man Jim Dowell bought the company from the family and moved it to Baltimore where it's smaller but thriving under Jim's direction. Jim still grinds every cam personally, starts at 6am and grinds until 2PM, then he starts answering the phone and designing the best cam available in this market for Mopars Fords and Chevy's, although 60% or more of his business is still Mopar."
 
I'm supposed to hear from the machine shop today about the condition of the 340. I've been told not to give up on that block, and that machining it would probably be about half the cost of a new crate engine would be... which has turned out to be true!

I've priced a few things out, (heads, carbs, intake) and I'm coming close to finally picking the cam.

I've been told Lunati's Voodoo series are great. I've also been told Compcams Thumpers sound great, but are more for show due to the poor performance of the cam.
I'm afraid that some of these opinions are bias. I'm open to any company and line-up though, as long as my demands are met.

Hopefully, if the motor mounting ear can be welded back on, and if the block itsn't cracked I'll be putting it together next week. So far, this is what I'm thinking:

I plan on a .30 over bore, .10 decking on the block
.10 off the heads (new X-heads 2.02-1.60 65cc) will take up to .500 lift
.20 off stock crankshaft
KB Silvolite Hypert. pistons (6cc head, 6.123 rods)
10:1 11:1 comp. (hard to tell at this moment.)
2400+ stall on 727 Torqueflite.
Pump Gas (93)

I don't plan on bringing this car to the track, but it will be a daily driver. I want low-mid range torque, and a lopey idle. I don't ever plan on getting on the highway and going over 60mph. This is just to tear up the city streets, one block at a time.

Thanks for the replies! I need to remember to post questions closer to the weekend :)
 
krondo.wg said:
I'm supposed to hear from the machine shop today about the condition of the 340. I've been told not to give up on that block, and that machining it would probably be about half the cost of a new crate engine would be... which has turned out to be true!

I've priced a few things out, (heads, carbs, intake) and I'm coming close to finally picking the cam.

I've been told Lunati's Voodoo series are great. I've also been told Compcams Thumpers sound great, but are more for show due to the poor performance of the cam.

Hopefully, if the Motor mounting ear can be welded back on, and if the block itsn't cracked I'll be putting it together next week.

I plan on a .30 over bore, .10 decking on the block
.10 off the heads (new X-heads 2.02-1.60 65cc) will take up to .500 lift
.20 off stock crankshaft
KB Silvolite Hypert. pistons (6cc head, 6.123 rods)
10:1 11:1 comp. (hard to tell at this moment.)
2400+ stall on 727 Torqueflite.
Pump Gas (93)

I don't plan on bringing this car to the track, but it will be a daily driver. I want low end torque, and a lopey idle. I don't ever plan on getting on the highway and going over 60mph. This is just to tear up the city streets, one block at a time.

Thanks for the replies! I need to remember to post questions closer to the weekend :)
Click to expand...

Let's see you want low end torque but nasty idle?
ENGLE KV-60 .534 lift 288*duration 238*[email protected] 108cl
[this is a bad *** cam for what you're doing]
low end torque?
=It's called gears 3.91-4.30 as you said you weren't concerned with hwy use.
What ever you do don't get too small of a cam, you'll regret it, more then going with too big of a cam.
You can always add gears....
 
Krondo;

Look on line at the major cam manufactures catologs. In the begining pages, they have a few pages that talks about cams. Most of your questions are actually answered within the opening pages long with "What cam is best for me."

By the time you finish up reading this material, you should be able to pick your own cam. If worse come to worse, you can call up any of these manufactures and ask them for help and there opinion. HOwever, each manufacturer will give a opinion that can or will vary as much as advice from this board.

Know a few things about your car that will help in others giving advice and there opinion on the matter. The cam grinders will need to know;

Engine size, car used, car weight, tranny type, gear ratio that will be used, tire size would help and intended purpose of the car. To a lesser extent, RPM range the car will perform in. Though the cam dictates this, it can help zero in the focus of the choice.

IF you allready have some engine parts you want to use, this may limit the cams overall size or parameters. An example would be a stock intake and exhaust manifolds or a Victor intake and 2 inch headers.

2shelbys gave you Racer Browns number and it should be used. The company has been around for a long time and is widely known in the MoPar ranks as a excellent and superior place to get a custom ground cam shaft for your car.

Just remember, the one thing about camshafts is the opinions and ideas of the specs are an item under constant opinion by others. It is amazing how many people will give there opinion on what they would have used or what cam is better for your application.

Call Racer Brown with confidence.
 
I just got word back from the machine shop, and the block checked out. They magnafluxed it and found no problems. They were also able to fix the motor mounting ear that had broken off. I've asked them to re-magnaflux the engine since welding on cast iron is difficult.

I gave Jimmy a call at Racer Brown and he was very helpful. I think we might be doing business here pretty soon.

Thanks for all the input guys!
 
krondo, you can never know too much about the camshaft of your car. when in doubt, always err to the smaller cam. It may disappoint you with it's smoother idle, but the car will be much more fun and livable to drive every day. To pick a cam by sound is the last thing you want to do for a street car, but, there are some grinds now that are designed for just that. Look everywhere, talk to the tech lines, Comp kinda sucks for in depth tech, but they are usually ok for newer enthusiasts. Engle as 340 mentioned, is another custom company that is very good to talk to, reasonable in price, and excellent in quality.
 
Experience plays big part in cam selection. What one feels is easily streetable, another guy will say it sucks, won't idle in traffic, pulls at stoplights etc. The lighter the car, the more gear, converter and compression the engine has, the bigger the cam you can run. Don't forget about running power brakes too. You'll need 12" hg in gear (on an auto trans) at idle to run power brakes without a vacuum accumulator or electric vacuum pump. Some will say you only need 10" but that's a stretch and we are talking brakes here.

I agree with Moper. Don't go with a cam based on sound but go with a cam based on your combination. Too big of a cam will be miserable on the street.
 
krondo.wg said:
I just got word back from the machine shop, and the block checked out. They magnafluxed it and found no problems. They were also able to fix the motor mounting ear that had broken off. I've asked them to re-magnaflux the engine since welding on cast iron is difficult.

I gave Jimmy a call at Racer Brown and he was very helpful. I think we might be doing business here pretty soon.

Thanks for all the input guys!
Click to expand...
You are welcome. Good decision. As I said, Jimmy is the best. You'll be glad you worked with him and you will learn a lot in the process.
 
I would stay away from Hughes cams.I know of many Hughes cams that went flat.I personally had 2 go flat on me.My second cam was even installed by Dave Hughes himself.I have used many cams over the years and have only have had trouble with Hughes garbage.Dave says his cams are the only real MOPAR cams out there.Well who in the hell is Mopar Performance??Mopar Performance don't make real Mopar cams??Ask anyone who works for Mopar Performance about Hughes cams and they will laugh in your face.Don't get me wrong Dave is a smart guy.But besides his cams I know of more than a handfull of his engines that have gone bad in the last few years.I even live less than 10 miles from Dave Hughes and I stopped using his services and parts about 8 years ago.Myself I use Comp Cams now and have had no trouble with them.They work really well.They also have a great tech. line as well.
Jim
 
Dave Huges bases his comment on there cams ramp rates being the most advantagous taking of the MoPar .904 lifter diameter. Which is not allways the best thing to do.
 
If you want the choppy sound with good street performance then you should ask Comp about the Thumpr Cam line. I have about 1000 miles on the Muthr Thumpr roller cam and I am very happy with it.
 
The other nice thing about Racer Brown cams is that you do not have to degree them. Yes, you have to make sure it is installed correctly but the installed position is selected and ground into the cam for your specific application. There are several great cam manufacturers out there but Racer Brown is the only one that will give you the perfect cam for your combination and stated purpose.
 
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