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1moparman said:
how do these ported 302 compare to unported edelbrocks obviously ones a close and ones a open chamber but I was curious about the flowing aspect
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Being that these are 2 totally different heads, with very different port sizes and shapes that there really isn't a comparision. Also the Eddy's will have much too large of intake runner for the 318 and kill low rpm performance and Tq. and worse than useing a 360 head on a 318.
The problem comes from the 318's bore size and not being able to use the amount of port volume that the 360 and or the Eddy's have. In short the bore of a 318 is just too small to pull effectively. This is why the engineers made 2 different heads for the LA engines. As they saw that one head wouldn't fit all.
As for the comparision that you want, first you would have to know how many cc's are in each head and then flow both heads. Useing the size valve that comes in them. Now if the 318/302 head which should be 118/120 cc's and the Eddy's are about 168/170 cc's then the flow will have to show a 29.5 % better flow numbers. So if a Eddy head flows 250 cfm's then the 302 head should flow 176.5 cfm's which is what they flow from the factory. In my dealings with the Eddy's they only flow 244 out of the box from Edlebrock. Now in a fully ported Eddy they flow in the 295 range with a 173 cc runner and a 2.02 valve, so now for comparision the 302 head.
The 302 head with gasket matching and bowl blending should be about 126 cc's with a 1.78 intake valve, this is a 17.2% reduction in port volume and a 12% reduction in intake valve size. So now if a Eddy flows 295 with a larger port of 173 cc's take the 295 cfm's X 17.2% and you would come up with 244 cfm's. But wait we still haven't figured the intake valve size difference in yet. Which is another 12% less area for valve sizes, so now the 302 head should flow 214.72 cfm's to be equal in port velocity and flow. But now this becomes interesting as the 302 head done correctly should flow in the 216-220 range and not being fully ported. With the head being fully ported it should flow in the 220-230 range.
This would show that the 302 heads on the 318 block bore size would be a much better head for performance and power, with better throttle response and Tq. due to higher port velocity and a ramchargeing effect.
Hope this expalins it better for you.
 
BJR Racing said:
Being that these are 2 totally different heads, with very different port sizes and shapes that there really isn't a comparision. Also the Eddy's will have much too large of intake runner for the 318 and kill low rpm performance and Tq. and worse than useing a 360 head on a 318.
The problem comes from the 318's bore size and not being able to use the amount of port volume that the 360 and or the Eddy's have. In short the bore of a 318 is just too small to pull effectively. This is why the engineers made 2 different heads for the LA engines. As they saw that one head wouldn't fit all.
As for the comparision that you want, first you would have to know how many cc's are in each head and then flow both heads. Useing the size valve that comes in them. Now if the 318/302 head which should be 118/120 cc's and the Eddy's are about 168/170 cc's then the flow will have to show a 29.5 % better flow numbers. So if a Eddy head flows 250 cfm's then the 302 head should flow 176.5 cfm's which is what they flow from the factory. In my dealings with the Eddy's they only flow 244 out of the box from Edlebrock. Now in a fully ported Eddy they flow in the 295 range with a 173 cc runner and a 2.02 valve, so now for comparision the 302 head.
The 302 head with gasket matching and bowl blending should be about 126 cc's with a 1.78 intake valve, this is a 17.2% reduction in port volume and a 12% reduction in intake valve size. So now if a Eddy flows 295 with a larger port of 173 cc's take the 295 cfm's X 17.2% and you would come up with 244 cfm's. But wait we still haven't figured the intake valve size difference in yet. Which is another 12% less area for valve sizes, so now the 302 head should flow 214.72 cfm's to be equal in port velocity and flow. But now this becomes interesting as the 302 head done correctly should flow in the 216-220 range and not being fully ported. With the head being fully ported it should flow in the 220-230 range.
This would show that the 302 heads on the 318 block bore size would be a much better head for performance and power, with better throttle response and Tq. due to higher port velocity and a ramchargeing effect.
Hope this expalins it better for you.
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GOOD STUFF!!! That is what I like to see!! Explanation! I will be getting in contact with you again Bobby about my 302's (still have questions).
 
you are a wealth of knowledge okay I understand the ports are just to big to put edelbrocks on a 318 they would have no velocity so to speak , I have a various motor big and small. one I'm working on now is a 318 ported small valve j head with a single draw tru turbo turbo ( have to smog it first then the turbo goes on). also working on my 360 truck motor making a stump puller ( any suggestions on cam? is a performer okay?9.5 compresion headers intake ign typical stuff oh yeah its a 5 speed) now the reason I started reading this is I recently got a 67 barracuda original 273 and have plently left over 318 parts. and this sounds like the way to go only I'm lacking the 302 heads. sorry for rambling great site and a wealth of info.
 
As for the 318 with the turbo, this eliminates the head port volume issue. When useing forced induction the port volume doesn't come into play, as much, but you can still have too large of intake port even with a turbo.

For the 360 I would use something in the 220-230 @ .050 duration and a split centerline in the 103/113 range. This should do what you want.
 
BJR Racing said:
As for the 318 with the turbo, this eliminates the head port volume issue. When useing forced induction the port volume doesn't come into play, as much, but you can still have too large of intake port even with a turbo.
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It should be better to run a smaller port volume rather than large with a turbo because this will increase you throttle response and torque before the boost is there, then you can tweak manifold pressure(boost) to get the target HP. In general a smaller port head would take more boost to make the same power levels but the larger port head would not make the off idle torque and could be more subject to turbo lag.
 
may be a dumb question but why the dual pattern cam? whats the benifits of dual vs single? (since you brought it up, I thought I'd pick your brains). also you just mentioned duration and centerline no lift? is that because the lifts are all about the same per those specs. and finally what manufacture are those specs from. again sorry for all the questions but you guys are good!
 
1moparman,
Single pattern cams are ok but when running a single pattern cam as the centerline gets lower and the overlap becomes greater, thus needing alot more compression and not very streetable. Along with more converter and steeper gears. This is why cam grinders grind cams with lobe seperations around 108-110-112 then they advance the intake centerline 2-4 degrees, most grinders advance them 4* so you would have a intake centerline of 106 and a LSA of 110 and exh centerline of 114. Generally when they get lower than 110 they are single pattern grinds. Cams ground on a 108 CL is generally used on both sides, like 108 int. CL and 108 exh CL so this would be a straight pattern cam.

The main reason that they do this is for either racing or street drivability, the further you move the centerline back the more drivability you'll have. On a single pattern cam, the lower the centerline the more racey it becomes. Dual pattern cams also allow you to have better bottom end and more top end with the same cam. By moving the int. CL down gives better low rpm performance, and with the exh CL being higher gives better scavageing. This cuts the overlap down and will add cylinder pressure which helps pull in a fuel/air charge and helps to push out the burned gasses. They use these on heads that don't have real good ports, either in design or flow. This brings us to the next question about duration.

Now on duration, this value is how long the valve is off the seat. They have 2 different terms for duration. One is seat to seat or any value less than .020 from the seat. Some are as .006 some at .015 this is all considered seat to seat or advertised specs.. Then you have duration at .050, this value is generally less than advertised and is more widely used for cams with more than 230* duration.
Cams with less than 230* duration are ment for street and have slower ramp speeds and more driveability. These cams usually have 110 or 112 centerlines and are ment for more Tq. and low rpms HP. These type of cams generally have very good mid range Tq and HP with flat or broad power curves. Cams like these generally are 2000/5800 rpm range cams.

The more duration at .050 the more radical the cam becomes and the faster the ramps get for opening the valves. Generally these are Race only designs, and too the lifter has to change in order to not cut the lobe off the cam. As durations at .050 get larger the taper or face of the lifter is ground differently so the edge of the lifter doesn't cut into the ramp of the lobe. Then when the ramp gets so fast they have to use a roller lifter design, as this is the only effective way that they could make a lifter live. Thus the new engines have fast ramp cams and use hyd. roller lifters. These make more Tq. and low rpm HP, along with smoother engine operation.

As for the lift question, lift is just a value that comes from how small or how large the base circle is. Most street cams have a large base circles and this allows the cam grinder to smoothen out the lobe or slow the ramp speed down and give you more advertised duration, but the actual time the valve is really open is less. Because the time that the valve really starts to open is later. Most race cams have small base circles and fast lobes thus creating more duration @ .050 and more lift.

From the cam grinders that I've talked to, lift is just a value to them and not really important. To them duration @ .050 and lobe centerlines are most important, as this tell them when and how long the valve will be open. You can have a cam that has only .450 lift and have 270+ duration @ .050 and 104 centerline. A cam like this will have the same effects as a very large roller cam but because of the large base circle can use a hyd. or solid lifter. And this is the type of cams that they use in Stock Eliminator Racing. So you can see that lift doesn't really mean much. Thats why they say it's just a value.

Cam grinders will tell you that if you pick a cam by lift you'll almost pick the wrong cam everytime. Or at least this is what they told me many many years ago. Since then I've bought cam profiling programs where I can put in the head flows and port sizes, rod lengths, and strokes, and bore sizes. These all have a adverse effects on the type of cam used. Along with the type of transmission and gears and weight of the vehicle. So you can see it becomes a science of more than just what cam to buy.

As for the specs. or who's specs.. I use Cam Motions and Comp Cams, and Crane Cams. Those specs. are just some that I threw out to give you a general idea as to what to look for. For street use in a 318 I like the 6901 cam from Summit. This cam is actually ground by Crane Cams, it's .441 lift on both sides and has a split duration like 218/224. Sorry for being so long but I hope that I stated it in such a way that you can understand it.
 
cut ..... paste....... archive............ thats alot of good info and a way better way to look at cams. I did just get the comp cams cam quest it is pretty neat. thanks for all the great info. on the cam note has anyone tried any of the vodoo cams. I think I read they have diiferent open and close rates (unsymetrycal could be the right word) on the lobes. thanks again
 
Dartboy52; Good add in. Of course, all things in balance and within reason. I can see where BJR was going with the statement.

BJR said; Sorry for being so long but I hope that I stated it in such a way that you can understand it.
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Sometimes, you can't be short and sometimes, you can't jam enuff info in a couple of posts even if coffee and crumpetrs are served. Cam's, of all topics, is not so easy to explain quickly without generating a ton-o-questions more.

1moparman. Sometimes more seasoned guys will pull my chain and complain I allways choose/recomend a off the shelf cam. These fellas balk at this idea of off the shelf cams. Not good enuff.

Well, most people here do choose them for the simple reason of they'll work and do well for there application. Chooseing a cam for the most part is not hard to do for a street ride or a street strip ride. But once your into racing heads up at the track for money, well, this may not be what you want to run in your engine.

The first thing that you, the purchaser needs to decide is what the car is going to be used for, at what RPM your engine is going to operate in, what gear ratio and size tire is going to be used to calculate the intended driving RPM of the car at the speed you OK with. Like Hwy. driving. Is 55 mph ok or should you consider 75 mph?

When you know that, you have preety much selected two out of 3 items of a cam needed to be known for your selection. Duration and centerline/overlap.

Then I tell people you need to know how well the head flows and where it doesn't flow so well. When you know that, that helps you in the valve lift department and depending on the purpose of the vehicle, how high the lift can go.

Everybody has an opinion on what cam is best. Everyone can argue there cam is better. Few will agree.
 
After I get the hedders done this week I'll get a video of it and get Rob to post it for me. Then next week I should have some ET #'s tow truck gas depending. Looking for low low 7's in the 1/8 or upper 6.90's and all out of a 318 and 302 heads. This engine may be for sale later on, complete less carb and dist. and hedders.
 
Those times are one Smokin' 318 there Bobby! Your posts keep me focused on getting the teen built when I start to wander on other options. I can't wait to see the results and video.
 
I have to see if I can get in the shop today to get the hedders done, Amos said that it would take about 2 hrs. to do as he came by and saw what I wanted to do. I'm crossing my fingers that they'er not too busy so I can get it done.
 
I tried to get a video of the engine and the hedders but my camera didn't like the viberation of the hedders (sound). But here it is anyway. I guess I'll have to wait to get the ET and have someone else take the video with a better recorder.

I tried to upload the video and couldn't so I'm going to have to have Rob or Adam get it uploaded.
 
The reason I couldn't load the video is the file is too large and I can't make it any smaller so next Sunday I'm going to the track for a little T-N-T everything is ready to go. Now just need to have the gas for the tow truck to get it there as gas is very scarce around here. And the lines at the gas pumps are 1-3 hours long. Heck they have people camping out at the pumps waiting for gas.

I know that I'm gonna have to do some tuning on the engine as the engine has changed a bit, by the hedders and the intake manifold. But it revs faster than it did before and sounds healthier, also too the velocity is stronger as I already had to de-jet the carb a good bit and may have to go further.
I put the tune up that it showed in the computer for the air factors that we had yesterday and the little engine responded very well. Before it spun 3-4 times before it would fire, and now if or when you hear the starter engage it's running. So I feel that now I'm as close as I can be until I get to the track. Man next week can't get here soon enough.

In the air that we have this morning it shows I should run a 1.48 60 ft. and 6.87 @ 102 @ 2876 ft. corrected altitude and 67* 30.12 pressure, but if the air is like what we had 2 weeks ago it would run a 1.53 60 ft. and 7.00 @ 100 mph @ 4833 ft. corrected altitude, so we'll wait and see what it does and how good the track is. I'll post either way on whatever it does. Lets hope for a good cool air day and low humidity. Then I can turn the spicket open and let'er rip.
 
I would just love to hear a clip of it running at idle. Can't wait for a full clip.
 
Adam,
I'd love to but I tried to E-Mail to myself and I couldn't do that either. I have the camera set to the smallest setting and the pictures have been resized by the computer and it says that it's still too large of a file. So I don't know how to get it smaller or what to do. Machinist I am not a computer wizard...........lol

Maybe if I didn't take as long of a video that I could get it to load, well the neighbors aren't going to like me this morning,..............hehehehe
 
Adam,
I took 2 more videos and sent them both to you to upload tonight, they are a good bit shorter but hey at least I was able to send them. The sound isn't so good though as the throaty sound of the engine messes with the mic. in the camera.
 
BJR Racing said:
Adam,
I took 2 more videos and sent them both to you to upload tonight, they are a good bit shorter but hey at least I was able to send them. The sound isn't so good though as the throaty sound of the engine messes with the mic. in the camera.
Click to expand...


Stand about 150 feet away maybe that will help.:-D
 
Now all I have to do is finish the cleanup and painting, then a set of Moroso Valve covers. So guess what I'll be doing sometime this week or Saturday.
 
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