The Dodge Challenger Message Board

Hay all,

I'm going to build a 440 to replace the 340 in my car next winter so I'm collecting all the parts I need this year. But now I'm looking at which cam I should buy, but i'm not that smart with all the diff specs.

From what I read/heard so far:
- the more duration, the longer the valves stick open.
- the more duration, the higher the rpm power range.
- the more duration, the rougher the engine is.
- the more lift, the further/quicker the valves open.
- the more lift, the more power the engine makes.

Is this right and/or are there more simple facts?

So far I was thinking of the Hughes hydraulic cam 3844 or one step higher...what do you think of that cam Dave? What I want is to build a 550-600hp 440 with a very rough sound... what specs should i need from your opinion? I do want a hydraulic cam because I will install a geardrive. Then you don't have any 'play' in the engine as you would have with the chain. And then with a hydraulic cam, you still have something. (you know how I mean this?)

Thanks

You have basicly got it right. The best way to compare cams is not only the amount of lift but how much it gives you for the amount of duration.

You want as much lift with as little duration as possible.

The 3844 is the one I use. I use it with 1.6:1 ratio rockers which give even more lift.

This requires something like their Stage One heads or standard Edelbrock heads to work. Anything bigger than this cam needs more head work. So it is Hughes Stage Two heads or Stage One ported Edelbrock heads or something of that size.

I would personally not like a bigger cam in my car. It drives well and is capable of running high elevens on the drag strip. Anything more and it starts to become a race car and not a steet car. It is scary enough as it is!

I also would not use a gear drive. They make a lot of noise and are expensive. A good quality true double roller chain is fine.

I used to run a gear drive on the street because I liked the sound, but I found that after about an hour of driving the noise just drove me nuts! I wouldn't use one again. Also, gear drives are only made for 3 bolt cams, I'm not familiar with the cam you are referring to but a lot of hydralic cams are only single bolt. The billet timing chain set made by Rollmaster seems to be regarded as the best quality at the moment.

That's what I love about the geardrives, that sound it makes... and it's not a problem cause most of the time I only drive for about 15-30 minutes and just a couple of times a year one hour, so that's ok. How do you change to a 1:6 ratio Dave? Is that possible with a set of 906 heads (thanks Hugh) with 2.14 intake valves etc.? Offcourse I do want the high lift but not to much duration, cause i rather want low end power then high end power. I think this cam is a nice 'between way' to work with. Is it then effective to use other components (manifold) to create more low end power or will it lose driveability? Cause at the stoplights I will be able to burn some rubber without a problem...

The camshaft is the deciding factor. Everything else has to match IT. You can't mess around with the spec of other components. What you fix to your engine has to match the cam. No argument.

If the heads are not up to flowing the correct amount forget running good times. You want as much flow as the cam and valve lift allow. More volume than you need in the intake runners is almost as bad as not enough. They will both kill performance. Match the heads to the cam you choose. A pair of 906 heads with oversize valves is not good enough for this cam. You need good quality porting or stock Edelbrock. Otherwise you may as well stick a milder cam in. Use any rockers you want on these heads but make sure you don't use the type with springs between on the rocker shaft.

Likewise the intake manifold. At this level you can get away with a six pack intake or a Edelbrock performer RPM intake. Both should be slightly ported. No other dual plain will flow enough. Anything bigger than this cam will require a large single plain intake.

With this cam you will loose your bottom end torque. As you will need a 10" convertor you will have nothing much below 3000 rpm anyway.

But don't worry about being able to burn rubber Hans. It will. Oh boy it will.

Oh and you will have to drive for more than an hour to get to the Mopar Nats in England this summer Hans!

Some basics in other words: Raising the amount of valve lift tends to improve the low-end power (for any given duration), while increasing the duration at a given lift tends to increase top-end power. (from "383 wedge work" by Eric Rickman)

My idea of camshaft selection is that if you choose a cam with duration above 284 degrees you will start sacrificing a great deal of low-end torque (which is nice to have on street cruising).
If you go above that, you have to live with the drawbacks on the low-end but you get a lot of top-end power.

By the way: How much duration and lift has this cam?

LIFT.
INT (WITH 1.5:1 ROCKERS) .536"
EXH (WITH 1.5:1 ROCKERS) .540"

INT (WITH 1.6:1 ROCKERS) .572"
EXH (WITH 1.6:1 ROCKERS) .576"

DURATION.
INT @.050 LIFT 238°
EXH @.050 LIFT 244°

ADVERTISED DURATION
INT 283°
EXH 291°

Lobe Separation Angle = 108°

I find the power feels about half in by 2500-3000 rpm and peaks at about 5700-5900 rpm. Shifting at 6500 seems to work best. Cruise along at 40mph and floor it and it gets up to 100mph in a blink of an eye - not that you dare blink. Low end acceleration seems quite good too but not as good as when the rpms are up a bit. 0-60mph is about 4.5 seconds. Hard to tell with the wheels spinning so much.

well about these heads Dave: 906 heads, 2.14 intake valves, 1.81 exhaust valves, the right retainers, springs, valve guides etc. and a good flowjob. Wouldn't work that you think dave? But when I choose a cam with lower duration i also will have a lower lift... so I will loose power because of that. I know about the need of a convertor, no problem.

Right now I have also a 244 duration at 0.050 lift so the power range of the cam I mentioned will be same as I have now, isn't it? And what about a 440 tunnel ram intake manifold...at least it looks good

I'm definitly not come to the nats with a 440, that's for next year. maybe I try to come with the 340 in it...

If it is a professional job on the head runners it will flow enough for this cam. Go for it mate. If you really only drive a very little you could try the bigger cam but I personally wouldn't.

A tunnel ram can be made to work but a good quality single plane or hi-rise dual plane will be better. It is not the length of the runners but the size of the plenium chamber. Makes them terrible at lower rpms. Tunnel rams on street cars was a 1980s fashion thing.

The single plane will give you the most peak power and the dual plane (Edelbrock RPM) the best lower rpm torque.

If you already have a 244 duration cam what is the lift?
If the Hughes cam has more lift (which it should) then you will find that the power curve is the same shape but with more power over the whole rpm range.

The cam I have right now fitted in my 340 has 244duration@050 at the exhaust and lift at intake valve is 0.488 and at the exhaust valve is 0.510. This is the edelbrock rpm cam. (working without a special convertor)

How do I know the maximum lift an engine can handle because of the valve-to-piston clearance? I'm thinking of the Keith Black pistons (the 933gram ones from Hughesengines). Any experience with these.

So if I want more low end power I should take a less duration cam (2330BL) with the 1.6 ratio to keep the high lift/power... Doesn't that hurt the performance you think. But then I don't have the rough idle which sounds great.

"Lucky" the tunnelram makes the engine terrible at low rpm, it drinks as much fuel as you drink beer (from what I read sometimes) so that one is off the record. Will go with something else thirst. Maybe something which accepts my existing 750cfm edelbrock. What kind of manifold you use?

My pistons are the KB type with the rased 'D' that filles the quench area in the combustion chamber. Conpression ratio is about 10:1. There is plenty of piston to valve space.

I use a modified six-pack induction Hans.

I think you really need to decide what your intended purpose for the car is and start from there. I designed my engine around the need to run 12 seconds flat in the quarter mile. Plus I wanted it to look as much like a standard 440+6 as possible but with a lot of the clutter removed from around the engine. Nothing that looks flash. Everything with a purpose.

Decide how you want it to perform and go from there. But the heads and cam not only have to match each other but they also dictate how all the other parts come together. Everything has to work as a team.

In about a month or 3 my 'parts connection' will take a 440 block with forged crank out of the US to here, after that they will overbore it with a plate at 0.030 over the stock size (if possible offcourse) so I can go bigger in the future if needed. I will use the stock rods with the KB pistons I mentioned before what will give me a CR somewhere around the 10:1 - 10,5.1. This with the 906 heads as said. Oh, and the geardrive. Besides this I haven't figured out the rest of the parts because I couldn't made the decision yet if I wanna turn the car into the higher rpm range or turn it into a mean torquemachine.

I'm doubting between the 3844 cam and match it with the right manifold etc. or taking the 2330 cam (with 1.6 ratio) and go for the low-mid end power. The advantage of the 2330 is I think, it has quite a big overall range, it gives good power from 1600-5700rpm. In any case I don't want the 'lower' cams from hugh, these are more made for 4x4's...from idle-3600rpm. The only thing that's to bad of the 2330 is the fact it isn't that rough.

And concerning the purpose of my car, it won't see the strip more then twice a year. Only streetraces will be winned with the car. But while typing all this I realize the following...

I can throw in the 3880 (1.5 ratio) and a 3.55 rear axle so you drive high rpm at low speed. I have played with your math spread sheet on the site and that resulted in the following: with a 3.23 axle and 25,4" tires (the combo my car had a month ago) it will run +/- the same rpm@60mph as with a 3.55 axle and 28" tires. And with the first combo and the 244 dur. cam (same as 3880) my car spinned the tires easily at the lights. So it would do this again with the second combo and the 3880 cam AND you go also fast at higer RPM's. Or maybe with the 3.91 axle, off course, that's why you still feel a good low mph/rpm power.

As you said I need to figure this all out before I buy anything more including the center section. Would be a waste of my money which would result in not be able to make it to the nats. Pff, and this with the find-and-land method, my fingers are getting tired man.

thx Dave

Use 1.6:1 roller rockers in any case no matter which cam you go for. It is basically free horsepower. I use Indy Cylinder Heads rockers with their shafts and separators. Cost about $350 if I remember right.
I love them!

Max cam-duration for the street? HRM, may ´92 says that long duration (over 220 at .050-inch tappet lift) gives the engine more time to charge and evcacuate the cylinders at high rpm. This improves top-end power at the cost of low-rpm torque.

CC, nov ´90 suggests that a pure street big-block should not have a duration above 216 degrees at .050 and the same magazine writes that a street/strip big-block (hydraulic lifters) should not have more than 250 degrees at .050.

I would agree with that. Except that I would put 250 degrees @ 0.050 as an absolute maximum for the street and would not go that far myself unless it was for a very low milage 'street legal' rather than a 'street driven 3,000 miles a year' type car.

The problem in general with taking things to extremes is that you take away all flexibility.

This also depends on what cam you take, a hydraulic or solid. With the same duration the solid cam gives power at a lower rpm then a hydraulic cam with the that duration. So you can pick a solid cam with a high duration while still having a good mid rpm potential.

By the way, I let go the idea of installing a geardrive, cost about $300 more then a good double roller chain. So now I'm planning to go with the chain and a solid cam from hughes. Still power at 2000-2500rpm and a good rough idle. The rougher the idle, the better the sound. Although that's my opinion.

But Dave, about that valve-piston clearance we discussed about earlier, how can I find out what the maximum lift can be before I choose a cam. This because the solids have more lift then the hydraulics, so maybe I should stick with the 1.5 ratio?

Oh yes. Solids are another matter. But I was not aware that there was very much difference at low rpm.

Hughes will advise you on max lift with any combination. But working out how much clearence you have at any part of the piston stroke is complicated and depends as much on valve timing as valve lift. It makes no difference how much lift you have if the piston is down the bore at that time!

So what you need to know is what the valve lift is during the few degrees or rotation that the piston is at or near TDC. Then compare that to piston height in the bore at that time (including gasket and taking into account the angle of the valve to the cylinder).

Much easier to build the engine and put some childrens plastic clay on the piston top as you rotate the crank by hand.

Hey Dave, now you learned something... It's simple to compare these facts at Hughes site. It shows the rpm range for each cam he has. I understand it's hard to figure the max lift out I see, better ask it Hughes when buying a cam. He will have more experience with these problems.

I was looking at the cam HEV4550BS, 250 duration@0.50]" and 0.575" lift at a 1.5 ratio (all on the exhaust side) although the high duration the RPM range is 2200-5900. Throw in a good convertor and some matching valvetrain components and you will have good power. Off course you still have to match the rest of the engine with this cam, as dave said before.

I just layed my hands on a complete 440 with trans for a good price so the work can begin...

I am a bit afraid that you are on your way to build an overcammed engine ,Hans.

I found a text in CC apr ´86, that is worth thinking of: Too much cam can create an unlivable environment for a street machine, causing loss of low-speed vacuum (killing vacuum-actuated accessories such as power brakes), rough idle, poor mileage, and terrible bottom-end response. In street applications, valve lift specs in the vicinity of .500-inch or less, combined with 260 to 280 degrees of duration, offer an excellent launching point for further experimentation (although variable-duration lifters will allow for more radical cam profiles without sacrificing low-speed characteristics necessary for survival between stoplights).

I agree with the text except that the valve lift needs to be less than .500. As Dave has written, we mopar-fans can take advantage of our large diameter lifters.

I think that Dave´s cam is hot enough for most street applications and that it is a good choice if you want to be on the hot an racey side, rather than on the mild street side.

A hazard, as I see it, is if you choose a very though cam you got to have quite high idle-rpm, and that is something I don´t appreciate.

I agree with you Christer. It is easy to go too far and build something that you hate to drive. But Hans is intending to drive this car very, very little (less than an hours drive anywhere was it Hans?) so he might be able to live with it.

I have my idle speed set at 850-900rpm at the moment. I would not like it any higher. It will idle on the driveway at 600-800rpm but it tends to stall at junctions set that low.

Have you considered a roller cam Hans? You could go quite wild with that and keep it drivable.

I thought the higher the lift the more power the engine can produce so that's about the lift. But about the duration, the cam I use right now, an edelbroch performer RPM has about the same normal RPM range as the cam I mentionded last time, just with a higher lift. So doesn't this mean that the cam will have about the same bottem-end response as my existing cam but gives more power in the right RPM's cause of the higher lift? I know about the problems you mentioned, but i like the rough idle so that's no problem and a poor mileage... horses will drink.

well Dave, in about 2,5 hours I could drive around the whole netherlands, it's not that big. Most drives, except the ones to big shows in belgium, germany, UK? will take less then a hour of driving. But I will consider your comments guys and will also take a look at roller cams Dave, have never looked at these cams. Otherwise maybe I have to go for the solid cam one step milder then the one I mentioned.

BTW, that solid cam has almost the same specs as the cam Dave uses. The lift is the same (0.575 vs 0.576) and the duration is just slightly higher. (250 vs 244) But there's no problem yet, the engine won't make it's debute before next winter, first I wanna drive this comming summer!

Final observation....
Hi,
All here is very interesting but I think You have no consideration for a big thing, the c.i. of the engine...
Think that : the 440 magnum has max horsepower at 4600 rpm; the 383 magnum with same heads, cam, rockers, and so on, peaks a 5200rpm....
If you stroke and bored out your 440 and remain with the same cam top rpm will be even lower..

That is right. The bigger the engine (or the more boost from a supercharger) - the more tame the cam will 'feel'.

Yeah, but I won't stroke my 440... but you are right about it Ciampone. Although I never thought about it. This would say the bigger the c.i. the wilder cam you could choose while keeping driveability. But the 440 I got my hands on has still a stock bore so I should pay attention to this. Oh, and reading the ideas/comments of you guys helped me a lot, thanks!

I will choose a cam with a little bit less duration as I first wanted. Maybe will keep it to the HEV3945BS, (245 duration, like I have nat the moment) with a 1.6 valve ratio, this cam works from 1800-5800 RPM. Another problem if you go 'bigger' is that I have to raise the C.R. too. Yesterday a mate explained me almost everything about these cam-topics so again I learned something.

Dave,

Is the Hughes HE2330BL the biggest cam you'd recommend with stock 906 heads on a 440? I'm looking for power around 2000- 6000 rpm.
Note: I love rough idle

Many Thanks

Tim.

Just to take a bit of guesswork out of the question, I'm using an Edelbrock torker 440 manifold (but could be changed to a Torker II if more suitable), and a 650 double- pumper carb.

Thanks again.

Tim

Couple of question first.

Are you using headers and what size are they?

What gears are in your axle?

Dave,

Will have to check the headers (came on the car), but I think they're either 2 or 2 1/4 inch.

Rear gears are 3.91 Richmond.

Hope this helps.

Ta.

Tim