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yet another 318 cam thread

I didn't know that any TQ was smaller than any 600. And besides the suspension difference with the 72 being solid mount k frame and rear end and my 78 having the iso-crap your 72 would otherwise be veryclover to the same car as my 78
. About the same size of a car anyway
And I assume that the 214/224 that you mention is at 0.050? That's where alot of the confusion comes in regarding cams to me. 256, 252 and 260 are all more than 214 or 224 so to me that means that the valves are held open longer with the 250-some cam than with the 214 or 224 numbers.
So then the (if I'm remembering the numbers right) the stock 318 cam at 240/248 is bigger than the 214/224?
I'm not looking at the numbers right now on this either but I believe that when I looked at the 252h and 260h both intake and exhaust were the same like the melling cam was. I see what you mean about the 256 being different on intake and exhaust but the cams I (was) looking, at weren't
 
Sorry I should have used a better cam reference. 214/224 was at .050” tappet. A stock 318 cam is down around 170-180 at .050” if I remember correctly, I would need to look it up for the exact specs. The comp 260H is 212/212 at .050”. The 214/224 was the same grind that people know now as a step up from a RV cam or summit 6901. It had a “Advertised” SAE rating of 288/298, they also Advertised it as 280/290, which is fairly close to what the cam had at .006” tappet. The .006”is what the aftermarket companies like Comp and Lunati use. Summit has the 214/224 cam listed as 272/282 also, kind of their “acts” like number.

Don’t feel bad getting confused by the cam ratings, even the seat timing ratings for the same cam (6400 Summit, big block version of a 214/224 cam, vary 16* degrees for the seat ratings, they are all the same cam!). The cam had 214/224 @.050 and 443/.465 lift. It was a good sized cam in a 318. We shifted at 5500 with that engine. But the power band was broad. We change the gears to 4.10s for one week and in top gear kept it wound up to 6700 RPM for a pretty good distance. It would have kept going too, I had to let off the peddle to keep it at 6700.

Use the .050 ratings to get the basic power band for a lobe profile. The seat timings are very important to, we use the seat timings a lot. But for someone that is new to cams the .050” ratings are more constant and easier to base decisions on.

I think the thermoquad you have in the attic would be about a 750 cfm carb, the same as what we had when we ran mid 15s with the 318. It sounds big, but the TQ’s are very forgiving on being oversized.
 
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I think this is the cam your 318 has in it now.

Mopar rating, roughly .008” tappet= 240/248

SAE rating (.006” at the valve) .004” tappet
264/265.

.050” specs
181/192

Lift
.373“/.4”
109 lsa
 
Yeah back when I did the erson cam in my cordoba back about 1987ish the cam I put into that engine (another 318) was supposed to be "a step above the RV cam" wasn't a stock replacement 340 cam (they had one listed as such at the time) bu it was supposed to be"real close to the same thing

that engine sounded mean but it was a bigger turd than it was with the original oem cam / somehow I figured that must have meant that it was "too big" and have shied towards "less than that" ever since.
Basically I'm looking for what would be like the proverbial "RV cam" as many we're described back around then, that cam description was very popular back around then which was also when I started driving and got out of high school.
I definitely don't want to wind up with a bigger turd this time around.
 
I was thinking that way originally... but just because it is free doesn't make it the right choice..... that's why I'm asking.
 
Markzx14 said:
Gear it lower and get the gearvendors od
Click to expand...
I'd probably swap in an a500 or 518 instead because the gear vendors seems to be made of unobtainium
My son has been looking for one for the 727 in his 440 powered 72 fury wagon (now his is a c body unlike mine)
Again one thing at a time. I have most of what I am wanting to put into the engine for an upgrade, except maybe the cam and lifters IF the 260h winds up not being able to work for what I want. I don't have another rear end or gear set for the existing rear on hand right now.
I do have a brand new trak Lok brand sure grip, that would fit in the rear end that I currently have. I had 2 of them but one found it's way into my daily driver 4wd dakota. But no gearset to go with it for this car on hand right now.
That would probably have to wait till next year. Like I said before no gears yet but that don't mean "not ever".
 
Dodge Bros said:
This Howards cam is worth looking at. It is a Mopar design. You can see the lift that can be gained utilizing the bigger lifter versus the comp profile.

255/261 @.006”
208/214 @ .050”
.479”/.494” lift 1.5 rocker arms
110 lsa

https://www.howardscams.com/hydraul...-273-340-360-1400-4800-howards-cams-711381-10
Click to expand...
But what will that do for driveability with that much lift? Again trying to understand how the different parameters effect how a given engine runs with one cam vs another.
 
volaredon said:
But what will that do for driveability with that much lift? Again trying to understand how the different parameters effect how a given engine runs with one cam vs another.
Click to expand...


Many cam mfgs list the durations at .2” lift. At that lift the piston is going down and trying to fill the cylinders. So long as the heads flow and intake track are capable of packing more air into the cylinders the extra lift and duration won’t impact the cams drivability and will make more power. If the engine is really efficient in moving air the drivability can even improve with more lift and duration at .2” tappet. At lower engine speeds the intake air that was polluted from the cams overlap gets sent to fill the cylinders. The more good air charge the cam stuffs into the cylinders lessens the percentage of diluted air that is mix in the cylinder. The engine’s cylinder pressure rises, making more power, and sends a stronger shock wave to expel the exhaust. That is why many smaller roller cams in combos that have good air velocity idle fairly well even though the cams spec’s are fairly big. They have more area under the curve for cylinder fill, and good velocity to pack the air in until the intake shuts.

The down side occurs with lift if the heads go turbulent before max lift. As long as the head flow does not drop the extra lift will not really hurt. But the engine won’t be using the extra lift very efficiently. On your stock 318 head the extra lift isn’t going to do much with out some port work. We did turbo system on a 77 318 and did some porting. I should have the flow number somewhere, I am pretty sure they went turbulent well before .5” lift. Once they were ported they flowed past .5” lift very easily. I would not use that higher lift Howards cam unless you use those later style heads or pocket port the stock ones.

With the stock heads and log manifolds the 260H would serve you pretty well. The XE256 is a better cam power wise, but a 260H in my opinion is a more efficient and would have better mpg than the Howard’s or the xe256 if your not going to run headers.

If it was my car I would do a small 250/256 from Lunati and have them narrow up the LSA from 112 to 109.
 
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agree with dodge
700 0r 701 from lunati or leave it stock
260 comp is too big for all the rest of the parts and gears you have
the howard is slightly larger than the lunatis
NOW
the seat duration determines driveability- and you have seen that you have to adjust for different ways of measuring seat
.200 is a proxy for area under the lift curve, a proxy for power
so you want it as large as practicle once you have picked your seat duration to set the rpm range
.050 gives a really rough idea but for a final choice is worthless
 
V
you should know by now that the way mopar measures duration is completly different than the way comp measures duration and even more different than the way Summit measures

V said "which, as mentioned above/ every single number for overlap, valve opening/closing degrees, centerline, was IDENTICAL to the COMP 252H..".
Melling uses the same method as Summit for most of their cams however I'd have to check, but many aftermarket sellers use factory advertised for stock replacement cams and SAE for others and they do not tell (some do)
 
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looking at that linked thread.... someone put a 318 cam in a 360.... I don't think Id ever do that..... but I was surprised, not much difference between the 2 cams (performance) in a 360.
 
volaredon said:
looking at that linked thread.... someone put a 318 cam in a 360.... I don't think Id ever do that..... but I was surprised, not much difference between the 2 cams (performance) in a 360.
Click to expand...

Lol...40 hp gain with the same rpm band with more power everywhere on a low compression basic build is HUGE.
 
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Curiousyellow71 said:
Lol...40 hp gain with the same rpm band with more power everywhere on a low compression basic build is HUGE.
Click to expand...
Im sure somebody did a test on a dyno of a stock 318 with a stock 318 cam and a stock 360 with a stock 360 cam, somewhere along the line...… which is what most of us are starting out with
 
I'd love to see the test done on a 318- stock cam then 360-2 cam.

If it's 40 HP on the 360, even 20 HP on the 318 might be worth it.
 
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