I've wanted to write this for ages but it's a bit job to do properly and I didn't really feel up for it. So I think I'll do a fairly quick first post compared to how it could be and then add to it once the thread grows and questions are answered etc. Just remember I'm not any kind of camshaft expert, but I probably have more dyno printouts of near stock cammed 304s and cam specs on file and more simulator time (100sx100s of hours than anyone else) so I guess if anyones going to write about this is has to be me.
For all of this we will be assuming a good exhaust and cam on a otherwise stock 304, stock compression, stock stall converter etc. And just writing about what is the most sensible cam for the job you want to do and why.
A bit of a basic theory about cams on a stock 304 is that you need to work around a couple of things, first the banana manifold which has very long runners and gets quite hot and the low compression of the standard motor.
Now in general the ideal sized basic standard kind of camshaft for this engine is something that makes power in the middle of the bananas ideal rev range and that's a normal cam of about 213/213 duration and 112 lsa, your typical Crane 276 is near this and you will often see people reccomend this as the camshaft where you peak in acceleration from standstill with a standard 304 that's kinda true if you were using cams with the same intake and exhaust durations but not if you get a bit sneaky, after this cam there's a plateau where theres no gain (you start to gain a little up top and loose down low untill about 220/220 degrees duration at which point you start to go backwards overall. By the time you reach 230/230 degrees you are going backwards almost everwhere on a stock motor (except for a very short time at very high rpm but overall the car will be slower).
Now, You can also have cams that have more duration on one set of lobes than the other, split duration cams. So with this you can do a couple of things. Normally with a weak intake on a street motor you will use more duration on the intake side and less on the exhaust and this is a good way to go on the 304, if you have or plan to run a good intake in the future and very good exahust you can go the other way around. Running less duration on the intake is also handy on low compression motors.
But! for some time now (since I bought my camshaft). I've realised that certain kinds of cams perform better than others on the 304, really you can hear the ones that are working better and to me the Crow 4503 allways sounded fantasic, this cam is 226/220 113LSA, has a fairly lumpy idle, it doesn't start to make more power than the stock cam untill 3500rpm but it makes good power from there on up and hangs onto the peak untill 6000rpm it does this because of the longer duration on the intake and catches the bananas "second breath" earlier than most other cams so it starts to gain again just around near 6000 rpm. but because the duration is shorter on the exhaust it's not totally full of fail at lower rpms. This is a good maximum effort cam on a stock 304, consider this the biggest cam you could get away with and probably really only for manuals with stock compression. Now if you were to use this in a auto you wont really _gain_ overall with the 4503 but you will not loose, your car will sound alot cooler and have a fair bit more top end power but it will definatly be slower off the line. Compared to a Crane 286 it will have a better idle, more torque and more peak power. Another interesting cam from Crow is the similar but smaller 4502, I don't know of anyone that has used this cam, but it follows the same theory in perhaps a more sensible sized cam especailly for an auto on the stock stall. This will run the same times as the 4503 but you will do so with 1 or two hundred less rpm on your shift points and that's allways a good thing, it'll be down a few hp on the top end but nothing much and it makes up for this with a little better low end. The Crow 4502 is 218/214 113 LSA.
Perhaps the most popular Crow cam is the 4770 (Crow stage 2) it's 214/226 111 LSA alot of people use this cam but I don't really rate it for use with the banana manifold it's more something you would use with another combo I mean it's not that bad of a cam and all these cams are similar in performance, but this one will be a tenth slower than the other two Crows and make quite a bit less top end power so it wont be so studly on a dyno run.
I'll add another popular Crow cam, the one with the angry idle the 4761 it's 230/230 and 109 LSA definatly on the downward slide as far as overall times goes on a stock motor but still faster than the stock cam (if you don't mind reving the thing to the moon and back) dont expect to see good times with this size cam unless you are shifting _well_ above 6000 rpm ie 6500 but most of these cams need you to shift up near there for ideal times. You could probably go with this one if a good manifold and more compression (optional) was in your future at some stage. Alot of guys with manuals get this one.
There's a couple other popular Crow cams but I think the 4502 and 4503 are the important two when using the banana manifold.
Moving on to the Crane cams, you have your 276, 284 and 286, we can skip the 286 here because thats only really a goer with flat top pistons and a big stall converter and not so good with the banana even then.
The 276 will make more torque than the stock cam and a little more top end, if you are going to want a cam with a daily driver that wont see high rpm you can do better and if you want a crazy sound and overall acceleration you can also do better so it's kinda a middle man cam, nothing too exciting I guess but a safe bet you are looking at 2 tenths slower than the 4503/4502 on this one.
The 284 everyones favorite cam loses some low end over the 276 and loses some over the stock cam, but it will hold top end power better than the 276 and over the full 1/4 mile will be a little quicker, about one tenth, so somewhere between the 4503/4502 and the 276 for 1/4 mile goodness. Over a short distance the 276 will be better, over a full 1/4 the 284 is better. Like I mentioned before the 286 is too much cam and will be going backwards so we will move onto Wade cams. I could have talked about the Blue racer cams which were the old Cam Dynamics range that Crane bought out but since Crane went broke I don't think you'll see those grinds come back again, the 276-284-286 probably will at some stage.
I made a bit of an error with the cam I choose which was a 214-222 from Wade (kinda) this is because I allways worked out the cam on the final specs I wanted in the engine in it's final form and that's with a very good intake but with a standard stall converter so in the end it's not really so good with the banana, equal torque down low to the stock cam but very much inferior top end power compared to some of these other cams, overall it's only a little better than the Crane 284 over the 1/8th mile where I'll be using it and similar over full track.
But Wade have a some more sneaky cams one that I really think is cool is the Wade 963A961A10 it's a tiny little thing at 203/213 but as an angry LSA for such a little cam of 110 and will make crazy grunt off the line (fair bit better than the stock cam) BUT it will also make more top end than the stock cam, this is a good cam, especially for a heavy car like a stato. Overal 1/4 mile times about the same as a 284 but better off the line and on fuel etc.
The good thing about Wades catalogue is that there's 1000 cams in there and you can if you want choose an intake lobe from any one of those and an exhuast lobe from any other and make your own cam from those, that gives you just about any grind you could want, I'm sure all the other smaller cam grinders will do the same from their catalogues.
Another great cam for the 304 is (oddly) a cam that's often used in the RB30, the Wade 818B1522C this is another of these turbo type grinds that happen to work well with the banana manifold this in theory should be the fastest cam (but almost identical times to the 5403/5402) we have talked about so far, specs are 222/212 109.5 LSA, the bottom end will be a little stronger than the Crows.
Other "turbo grinds" Wade do are the Wade 1522B1147B very similar performance to the above but 110 lsa and more duration at 224/218 if you wanted a more safe bet you would go with this one.
Anyway that's all I'm going to write today, hopefully it give you some idea about what's needed when choosing a cam for a engine where you are keeping everyting else other than the exhaust stock and remember from the stock cam to the Crow 4503 and 4502 we are only talking 2 and a half tenths and 3 or so mph but with much more top end power and more impressive dyno sheets. The bigger cams multiply the gains with a better manifold and more compression however all the above cams will no longer be the ideal cam in that case but they will be still CLOSE. And for a car that will slowly evolve I guess having a cam that can do a bit of everything is the best way to go about it. The smaller/lesser cams mentioned here will dyno around 170 rwkw and the better ones about 185 ish.
Also I'll add something about LSA, Lobe Seperation Angle, as a rule (depending on the total duration and some other stuff) Tigther LSA's ie 108 is tight 117 is Wide, the tighter it is the rougher the idle will be and the more concentrated the peak torque hit will be. Also the tighter the LSA the better headers you need to make it work, with a wide LSA cam like the stock cam at 117, headers do little compared to what they would with another tighter cam
Last edited by greenfoam; 19-02-2010 at 03:55 AM.
good to see you get back to this. you should do a bit about lift/ramp rates and springs to suit
Body by Holden, Soul by Brockthe Legend will live forever
VN exec T5: 15.1sec @92.2mph 1/4 mile, 9.7sec @ 74.6mph 1/8mile, 2.3sec 60ft, 0-60mph 6.827sec 22/11/07 Gtech competition
excellent thread mate i understand a little bit about choosing a cam now
So, jason, how do you reckon the Crow 4503 would go with say 10:1 comp?
My dad had the Crow stage 3 or 4503 in his HR (when it was a 5 litre, obviously ) and to me it seemed very doughy down low and that was with a 3000rpm convertor. Although, that was with the generic Crow tune, so that could have been a factor, but i always thought it would have really benefited from more Comp.
There's 3 or 4 different cams that can be the Crow stage 3, every time someone sends me a cam sheet for a "stage 3 crow" it seems to be something different so that's a bit of a trick too, up untill 230 degrees duration at least you can allways can back equal toruqe down low as the stock cam by adding more compression, the more cam then the more you can get away with but somewhere after that you can't get it all back. A friend of mine had one of the stage 3 crows (don't know which one) and it ran a 10.1 1/8th mile on that supplied tune, then 9.2 on one we knocked up for it (first try) so there's a fair chunk or difference there
This is the Crow 4771
This is another of the "Crow stage 3's dunno which one but probably also the 4771" Both these cars ran 9.2 1/8th miles at full weight
Here's the typical 218/222 cam in the Orange ute, the Wade 1522bc?cb? lol one or the other, the limiter is 6200 rpm for reference
And this VR had a small cam 213 duration I believe and slightly cleaned up heads, with a good twin system and x pipe, ran 9.0
but perhaps more skillfully driven than all the other cars above, this car made 165rwkw and had plenty of dyno time