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gen1dak
Dodge Dakota
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10/19/2004
23:47:11
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 Subject: RE: Head Porting
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Hey "Not so"... First of all, where do you get off doubting information when you don't even know the basic specs like valve size? I mean it's like, "Hi. I don't know what I'm talking about, and I doubt what you say because someone else said their example didn't do what you said." I don't know it all, but damn man. Just because KRC's package manages about 380HP (at the flywheel), with Magnum RT heads, doesn't mean it isn't within the capabilities of the heads. The intake flow at .600" is 190cfm on a stock Magnum head. MP lists the stock Magnum head, ported and with larger 1.97 intake valves as flowing 230cfm at .600". The Magnum RT head with stock 1.92 intake valves flows 229cfm. Alreadys, Magnum RT heads have shown over 260cfm with some creative port work. Now, this (.600" lift) is outside the street realm. Back it down to sub-.500" lifts, and they're a good bit closer. A 340HP head, which has an inferior flow balance between intake and exhaust will flow 200cfm with 2.02 intake valve, and they will nail 390hp without porting. The stock Magnums, while flowing slightly less on the intake side, have a much better exhaust flow than the 340HP (LA head), so the odds are actually a bit better for the Magnum. The examples I cite are 3 articles on 318 Magnum build-ups, as well as a 318 LA buildup with stock heads reworked to well-ported and re-valved 340HP specs, a 340 build-up, and a dyno run of an MP 380 horse 360 crate engine. The 318 Magnum conversions all had stock Magnum heads and a cam in the CompCams 268 Xtreme Energy or Magnum 280 range, except for MP's crate engine, which had an even nastier cam. The 380HP 360 crate unit actually managed 409HP. All the 318's managed just over 400HP in the high 5000 to just over 6000 rpm range depending on setup. The one thing in common? All consistently managed right at 400HP in the same rpm range, regardless of displacement.
One other thing on the KRC example. I'd imagine that was a fuel-injected package? The examples I cite are carbureted examples. This could easily account for the numbers, but it does not change the FACT that the stock Magnum heads will support 400HP at 6000 rpm's right out of the box and unmodified. Whether you want to believe it or not is irrelevant.
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Science Guy
Dodge Dakota
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10/20/2004
12:10:34
| RE: Head Porting
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gen1dak, well said! I tried to keep it simple for the "uninformed" crowd, but he kept coming back for more.
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Not So
Dodge Dakota
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10/20/2004
17:46:30
| RE: Head Porting
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Science Guy, you dont have a clue. You tried to keep it simple is a bunch of BS. There are no facts to any of your post's, all opinion. You tossed in the boosting reference which has absolutly nothing to do with the original post.
Gen 1, great examples but as you mentioned you are talking carburators not FI. The orininal post was about a R/T, a 01 R/T, that is fuel injected. You know that you cannot run anywhere near those cams in that set up.
BTW next time I will take three days to respond as you did to make sure I dont make a typo and put 1.8 whatever vs. 1.91 My mistake.
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gen1dak
Dodge Dakota
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10/20/2004
21:48:28
| RE: Head Porting
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Hey Science Guy...Thanks. You know, the thing that really bugs me is when the facts are disputed by someone who doesn't know better. I don't step up with an answer to every question because I don't know them all. There's nothing wrong with that. But for someone to say they "don't believe" something, but have nothing to dispute it with is such a useless position to take on something.
Okay "Not so", so now you're the cam expert? Take a look at the specs for the KRC 110X and the Xtreme Energy 268. The KRC 220 and the XE 268 are even closer with the exceptions of the 220 having more lift (good for HP) and a computer-friendly 114 degree lobe separation (better low-speed vacuum and a wider powerband). Duration is very sililar. The KRC 110X has a 110 degree lobe separation for better midrange torque (just like the XE 268), but still works with computers. Like I said, all-in-all, the specs are close.
The crate engine cam is not a PCM-friendly unit. The point, once again, is that regardless of the cam used (within a given set of parameters) and regardless of the displacement, they all were right at 400HP (390-409HP). The 360 pulled more on the heads than the smaller engines, yet still barely topped 400hp with the biggest, most horsepower-oriented cam of all the examples. That's about as obvious as it gets.
Now, if the heads are ported, it's easier to hit 400hp with a milder cam (again, milder to a point), but my response was to the ability of the heads to move enough air to generate 400hp at the flywheel, and people much more knowledgeable than I, say, and have repeatedly proven, the same thing. If the PCM and MPI are up to the task, they can make the same numbers. Deal with it.
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Science Guy
Dodge Dakota
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10/21/2004
09:43:42
| RE: Head Porting
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gen1dak, save your breath. Although you have enlightened me in some areas, Not So just won't get it and he'll just continue to flame.
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Eddie
Dodge Dakota
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10/21/2004
16:43:20
| RE: Head Porting
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Excuse me gentlemen, sorry to change the subject, but it's about head porting, gen1dak I have a question. I have a 99 RT with the basic bolton mods; tb, headers, pcm, 100 shot nx, ect. I'm looking to get some head porting done and a cam. Not sure on what size valves to get. I heard that the 2.02 were to big unless you have a blower and that the 1.92 are good if you have nitrous. Whats your thoughts. Thanks
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Not So
Dodge Dakota
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10/21/2004
18:36:21
| RE: Head Porting
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That would be a good question for Science Guy to answer. Give it a try.
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Science Guy
Dodge Dakota
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10/21/2004
18:44:18
| RE: Head Porting
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Velocity and pulses
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N56629
Dodge Dakota
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10/21/2004
20:05:50
| RE: Head Porting
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"Velocity and pulses"--SciGuy
Wow, that's really deep.
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N56629
Dodge Dakota
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10/21/2004
20:08:24
| RE: Head Porting
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"I heard that the 2.02 were to big unless you have a blower..."
You would think just the opposite would be true. Think about it.
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gen1dak
Dodge Dakota
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10/21/2004
21:09:37
| RE: Head Porting
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Eddie, for ported stock heads, I'd have the 1.97 (that's not a typo, 1.97, not 1.92) intake and 1.625 exhaust combo. The intake ports, with a good porting job, will flow 230cfm at .600" which matches an unmodified Magnum RT head.
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dartvader
Dodge Dakota
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10/21/2004
21:48:13
| RE: Head Porting
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I would not waste any money on porting the stock magnum heads,if you want to do it yourself that fine ,the stock magnum heads are pretty weak ,I've been through 2 pairs ,they crack right in between the valves,people that know say im running too much timing others say its common,bottom line start saving for those R/T heads..
ooh I forgot to tell you they are backorderd BIG TIME now .
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Science Guy
Dodge Dakota
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10/21/2004
21:48:19
| RE: Head Porting
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Now you've stooped so low as to pose as the "Science Guy" as stated on 10/21/04, 18:44:18. Let the record show that it was not I, but someone else who posted that response. I will NO longer, I repeat, NO longer post on this subject. Any further post by the Science Guy will be from the poser. Until another topic, Later
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gen1dak
Dodge Dakota
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10/21/2004
22:57:16
| RE: Head Porting
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Pretty much the same issue with 360 LA heads cracking in the same place, but this was typically on high mileage units. The 318 LA heads were much less likely to crack since they had more meat by virtue of having smaller valves and ports. 318 Magnums do not have this advantage. It comes down to the amount of heat stress they are subjected to, and that varies with performance mods including timing.
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Eddie
Dodge Dakota
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10/21/2004
23:00:37
| RE: Head Porting
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So do you recommend the same valve sizes for the RT heads, 1.97int 1.625ex? I'm just lookin for some good performance. I don't drive my RT daily nor do I race it every weekend. I take it to the track about once a month in the spring/summer time. Thanks
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gen1dak
Dodge Dakota
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10/21/2004
23:35:44
| RE: Head Porting
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Nah. With the RT's, they have an increased intake port volume (153cc stock vs 180cc RT). The standard 1.92's will deliver 229cfm at .600" right out of the box. Unless you really go for the big end on a cam, blower, etc, you're gonna lose a lot of low rpm power, and have under-used potential on the high side in a naturally aspirated street 360. So, no, I'd be happy with 1.92's in the RT heads for a flexible street engine.
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Eddie
Dodge Dakota
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10/22/2004
00:17:39
| RE: Head Porting
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Thanks for the info, just one more question. Can you explain the difference between 1.92 & 2.02. I know there are different sizes, but what application would they be used in.
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gen1dak
Dodge Dakota
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10/23/2004
00:05:01
| RE: Head Porting
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The 2.02's would get the nod for max effort engines and strokers where low rpm power (on a smaller engine) would not be a concern (and not an issue for strokers), but maximum airflow for max hp is. For a street engine, with stock heads, I'd stay within the 1.97 size maximum, unless it was a stroker. Highly reworked stockers may see some gains with the 2.02, but the airflow velocit suffers at lower rpm, and thus, so does the grunt. With the RT's and their larger port volume, you can feed strokers, or serious racing engines, and the usefulness of the largest valves really comes into being, especially since these heads are probably gonna be modified for even more airflow. It varies with package and head.
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adam
Dodge Dakota
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8/14/2005
19:12:45
| RE: Head Porting
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Heres some great info on magnum heads. And yes they will sapport 400 horse in stock form. You just need the right cam/intake/exhaust to do it.
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=366847&an=0&page=0#366847
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