Which Camshaft For This Brute?

[haywire 440]

You [ & some others ] are paying too much attention to advertised duration #s. The duration measuring points vary, generally from 0.004" to 0.008". Usually tappet lift, but not always..... The Comp is 270* is measured @ 0.006" of tappet lift. Some cams are measured at valve lift. So if you are comparing cams to say the Comp 270, a cam with 270 @ 0.006" valve lift is going to have less adv duration than the Comp because that equates to 0.004" tappet lift [ 1.5 rockers ].
Some of the cams listed above do not list this important info, so useless trying to compare cams that way.

I suggest you find D. Vizard's 128 rule on the web & calculate the reqd LSA [ It will be considerably tighter than 112....]. While it is for SB Chevs, he has claimed it works well for parallel valve heads....certainly better than GUESSING.

I did find the 128 rule and here are the numbers I come up with,

Intake Valve size 2.08 with the center line, using this formula, is 105.4 *(LSA) (*edited because center line is the wrong term)

Exhaust Valve size 1.60 the C/L is 98.2 *(LSA)

The Melling cam is 110 and 116.

I read that advancing the cam can lower the power RPM range of the cam. Would that have the desired effect of helping the Melling cam higher than optimal C/L?

And that’s why earlier you mentioned the 110 C/L of the Camcraft cam would be your choice?

I knew that comparing all 4 of cams initially would be like comparing apples to oranges because not all the specs categories are listed the same.

 

[haywire 440]

Run the Milling cam you have. It will work good with 9.5:1 or less compression.
At 10:1 compression, and the 4-speed you could go slightly larger.

The 4-speed does help with idle control unlike the automatic that can lug the low speed response.

 

[furious70]

I agree with the sentiment that based on how you plan to use it plus the melling is already installed you should just leave it that way.

 

[70bigblockdodge]

I did find the 128 rule and here are the numbers I come up with,

Intake Valve size 2.08 with the center line, using this formula, is 105.4

Exhaust Valve size 1.60 the C/L is 98.2

The Melling cam is 110 and 116.

I read that advancing the cam can lower the power RPM range of the cam. Would that have the desired effect of helping the Melling cam higher than optimal C/L?

And that’s why earlier you mentioned the 110 C/L of the Camcraft cam would be your choice?

I knew that comparing all 4 of cams initially would be like comparing apples to oranges because not all the specs are listed the same.

That 128 rule is for full getting as much power possible from engine. It is giving you the ideal recommended lobe separation angle not installed centerline. These numbers always look similar. Tight lobe separation angle will give the valves more overlap when both valves are open for scavenging, more overlap is generally for higher rpm (all the air in the engine is moving faster), this makes for a rowdy engine. Bad idle, poor vacuum, etc. at low rpm, not what you are looking for. Wider lobe separation angle will make engine much more drivable, more in line with what you are looking for.
Installed center line is lobe max lift in relation to piston position or degrees. Ideally you would want most lift when piston is traveling the fastest (most sucking), a little past half way down the bore, (crank at 90°-110°) 90° is a little early for air to "catch up" and hard to get the intake valve open far enough without a huge relief in piston (valve starts lifting as piston is coming up to TDC).
With lower compression you normally advance the cam to close intake valve earlier (after bottom dead center ABDC) and trap as much compression as possible. High compression will allow installed centerline to be backed up a bit to improve rpm capabilities.
I would use the Melling you already own at recommended installed center line, because you have decent compression in that older engine. Usually advancing the cam is done to build some cylinder pressure in a mid seventies engine without having to change internal parts, just putting a cam in it.

 

[Geoff 2]

The Melling cam would be the worst because it has a wide 113 LSA. This heavy car needs mid range tq, not higher rpm tq which wide LSAs favour.
Another DV comment: the right cam cost the same as the wrong cam....

There were some switched on cam grinders back in the day that 'got it'. They ground tight LSA cams. Isky cams were mostly on 108 LSA. Crower had a grind, a hot street cam for the BBM, #206-HDP that was on 105 LSA.

Below is a warning in the Erson cam catalog on too much duration for a 440. Although he doesn't state the reason, the reason is the very high rod/stroke ratio of the 440. This duration warning only appears on the 440 page. Hmmm....

 

[Geoff 2]

Here is another Erson memo, how tight LSA always makes more midrange tq.

 

[Geoff 2]

If you want more low end, smoother idle, you reduce duration. You do NOT widen the LSA. You can see this with Vizard's cam selections. Duration is reduced, but LSA remains the same for that engine size.

 

[451Mopar]

If your bracket racing with open exhaust use Vizards 128 rule.
The 128 "rule" is more of a baseline, as there are adjustments to it, and is based on maximum overlap scavenging with headers and open exhaust for a race application.

 

[Geoff 2]

Post #27 is a bit hard to read.
Basically it has engine sizes from 302 to 434 ci. It then has performance categories, from Street & Tow to Real Race.

Post #27 is just one section in DVs SBC book. There are other sections for roller cams etc.

However, each category is the same in these respects: Take Real Race. All engine sizes have the same duration. What changes with each size is LSA. It gets tighter with more cu in. That is because the bigger the engine, the more air it needs, so more overlap [ tighter LSA ]. 434 ci uses 104 LSA for all performance categories. For Street & Tow, the duration is much less but LSA is still 104.

if you think 104 is tight, Jon Kaase, multiple winner of the EMC, won with a Ford 400 engine that had a 98 LSA cam, 92 ICL.

 

[RemCharger]

If your bracket racing with open exhaust use Vizards 128 rule.
The 128 "rule" is more of a baseline, as there are adjustments to it, and is based on maximum overlap scavenging with headers and open exhaust for a race application.

We better check with Vizard., or better yet just buy a Vizard cam.

 

[451Mopar]

I think the Milling cam specs out like a stock 350 HP 440 cam, so smooth idle and such.
If you want to spend money on a new cam, call Hughes Engines (309) 745-9558
I think they might recommend something like their "real" 6-pack cam SEH2226BL-10 for street performance, or maybe slightly smaller if you want more of a daily driver type idle quality.
In my little 360 RV engine I am running the Hughes SER1620BL-12 with 1.6:1 rocker arms and it makes good power with having a fairly smooth idle.

 

[451Mopar]

Geoff, can you upload higher res images? I tried downloading them and magnify them, but the text is too blurry to read.
What do you think of the Hughes cam? or what specs are you thinking would be a good match?

 

[Geoff 2]

The 128 rule is NOT for a race application, & DV has stated this in his videos. It is for engines with comp ratios between 9.5 & 11:1. What he DOES say is that it is a good guide for ALL engines & much better than ringing a cam company & getting advice off the phone jockey reading from a computer....

 

[furious70]

I would want to verify with any EMC competitor that their engine would really perform daily in a heavy street car and not just under the rules of that competition on a Dyno...

 

[70bigblockdodge]

The 128 rule is NOT for a race application, & DV has stated this in his videos. It is for engines with comp ratios between 9.5 & 11:1. What he DOES say is that it is a good guide for ALL engines & much better than ringing a cam company & getting advice off the phone jockey reading from a computer....

Yes, but you will have to cut the duration so much the cam will be worse than if you just bump the LSA upward to gain driveability. Yes it will lose in areas in the rpm range otherwise they would only make one cam for a engine, that would obviously be easier from a manufacturing/ company standpoint. One size does not fit all, hence the shitpile of cams offered by all the different companies.
Besides he already owns it.
I think the parameters was to chose one of the four listed because he has those or access to those.

 

[Geoff 2]

No not at all. Not all factory cams have wide LSAs like US engines. The 850 Morris Mini had a factory cam of 230* adv duration......& was ground on a 107.5 LSA. You can be sure it had a smooth idle. That was the smallest cam. Bigger engines such as the Morris 1100, Sprite 1300, Cooper S had cams with more exh duration but the same 107.5 LSA. These were factory cams. Some aftermarket cams were ground on 102.5 LSA

 

[mgoblue9798]

The heads are redone already with the stock springs installed, a valve job done and hardened seats installed for the 1.60 valves.
This build was based on keeping it as close to stock as possible. I was concerned about the Melling cam because of the advertised duration of 284 and 293 at .006. I was thinking that would create a rough idle.

It will probably be driven like an old man wearing a hat but maybe a good song might stimulate my right foot and right hand to row the boat a little faster. But I regress, rpm power range would stay below maybe 4k to 4.5k range. Also this is an air conditioned car so it needs to handle that stress at low rpm’s. That’s why I’m thinking it needs a low rpm torque range.

I’m also planning a full dual exhaust that’s is stock quiet.

Good to hear your feedback!

Call Mike Jones at Jones Cams. He has an RV big block fast rate of lift short duration grind that might be perfect for what you are doing.

 

[Rebelrouser]

Details: Vehicle 1965 Chrysler 300L
Engine: Original 413, .030 over bore
and hoping for 10-1 compression but it probably will be lower.
Heads: Closed chamber 516s with the small 1.60 exhaust valve.
Intake & carb: Stock 4-barrel
Transmission: 4-Speed manual
Rear Differential ratio: 3:23 Sure Grip
Weight: 4200lbs

Currently the short block is together.

The original cam had these numbers and is not being used.

View attachment 1497481

Next up is the cam from Melling and is now in the short block

View attachment 1497480

I wonder how the above cam will act in this heavy car. It will not be a high rpm use engine and looking for a lower Torque & Hp range.

Now two more camshafts are listed below. The first one is the recommended replacement cam from the Chrysler 300 International Club and is made by CamCrafters. The second is a Comp Cams RV cam that is new but 30 years, or more, old.


View attachment 1497482

COMP CAM specs are shown below in 2 pictures, the cam box and the card inside with the cam.

View attachment 1497483

View attachment 1497484
Which is your pick for this application?

Haywire is not sure.

Get yourself a good engine program. I use https://www.performancetrends.com/Engine-Simulation.htm If you take the time to input good numbers it will give accurate results. And it will predict a lot of things already discussed, like cranking compression, idle vacuum, will plot an advance curve, fuel octane requirements. And the book that comes with it will explain how an engine operates, it is worth the price of the program. Plus, it is fun to just see what works. And I have been using it for many years, and I have a real dyno, program is accurate within 10% on every engine I have used it on and then run on a real DYNO.

 

[451Mopar]

Geoff, I apologize. I was thinking of the over cammed narrow LSA engines I had. Reducing the duration to reduce the overlap makes sense.
Hot rod terminology can get confusing. "Low End Power" to a racer or dyno operator is 3,000 RPM, and about 1500 RPM if your talking 4x4s and street cars.

 

[Ray70Chrg]

I just read about the 128 rule today and watched several of his videos. Just for fun, I used his formulas for my stock 383 and came out with a desirable lsa of 103, and intake duration of 241.
Has anyone tried a cam with these specs and how did it turn out? Currently have a Lunati with 110 lsa and approximately 35 overlap. Estimated because cam card gives timing events @ .05 lift.
This is certainly much different from the usual recommendations. The advertized intake for my current cam is 268, 226 @ .05