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Author Topic: Shorty Headers worth it for a 360 Mag?  (Read 1483 times)

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Offline Slanted_Mind

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Shorty Headers worth it for a 360 Mag?
« on: July 14, 2004, 03:22:01 PM »
Curious as to whether anyone has any experience with smog-legal shorty headers on a 360 Magnum.

Rig in question:   My daily driver,

2000 Ram 1500 Sport Quad Cab
4x4, 360 magnum, 46RE (auto-OD), 3.55 gears, 33" tires
Flowmaster Cat-backs
Jacobs 8.5 mm wires
Jet Chip
K&N
Otherwise bone stock.

The cat back and chip made quite a difference in the 3000+ rpm range, but I would like a little more oomph down around 2k rpm.

This rig must be emmissions tested every two years...both visual and hooked up to the I/M computer (they don't stick the sniffer in the tailpipe of OBDII anymore ????)

Basically the only emmissions legal mod I have left is the shorty headers I found, and they are $400.  Are they worth it?  Or will I not see much of an improvement over the stock exhaust manny's?

-SM
« Last Edit: July 14, 2004, 03:22:52 PM by Slanted_Mind »
1978 W150 Ex Cab 360 2bbl/727/NP203/D44-8.25 For Sale
1987 D150  225/904/8.25  Not even close to stock
2000 Ram 1500 4x4 360/46RE/D44-9.25

Offline TheSasquach

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #1 on: July 14, 2004, 06:01:06 PM »
i imagine you would have a bit of seat of the pants power increase with the headers. on a side note isnt the Mopar performance cam for that engine C.A.R.B. certified?
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Offline Slanted_Mind

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #2 on: July 14, 2004, 06:52:50 PM »

i imagine you would have a bit of seat of the pants power increase with the headers. on a side note isnt the Mopar performance cam for that engine C.A.R.B. certified?


No idea, I have not looked into a cam as yet.  I have a sneeking suspicion a performance cam would make the power curve 'peakier' and move the power up in the rpm band.  I like the flat torque curve this motor has, but it could use a little more down low.  Possibly an "RV" cam in the future.  Either way, I won't be touching any internals until the warranty expires (another 2 years or 25k miles---and believe me the extended warranty has paid for itself twice over already).

With the cat-back exhaust I figure the breathing restriction is now either bewteen the Y pipe and catalytic converter, or the exhaust manifolds.  I haven't decided which. I am hoping someone has already done this and can give me some feedback; I don't want to shell out $400 and be dissapointed.  :-\

-SM
1978 W150 Ex Cab 360 2bbl/727/NP203/D44-8.25 For Sale
1987 D150  225/904/8.25  Not even close to stock
2000 Ram 1500 4x4 360/46RE/D44-9.25

Offline trojmn

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #3 on: July 14, 2004, 09:35:48 PM »
I have heard some very positive things about 1.7 ratio rocker arms improving torque and HP across the board.  Several people recommend this rocker for getting some low end torqe lost with the MP single plane intake.

I've got a 318 mag now in my RC and like it a lot.  Less very low torque than my 90 360 TBI but 40 more HP.  I have a 57k mile 5.9 ready to go and I will have no reservations of going to the single plane and 1.7 rockers installed in any order.

I was toying with the idea of running the 318 cam in the 360.  It has a BUNCH more lift than the 360.   I dont have the exact numbers but its like .468" v .408 on the intake. Does any one know the stock duration on the mag 5.2 and 5.9 cams?   I saw a MP can with lifts simliar to the 5.2's lifts but the duration is what will make or break it with the computer.

I just cant see the point in 1.5" primary shorty headers on a 360.  The MP mag did a bolt on buildup on a 318 mag truck and used shorty headers and 3" cat back and got <2HP.  Then they upgradeed the Cat and Y pipe and got 8 more.  It sounded like a whole lot of $$ for not much HP.  

Offline TheRamChargerMan

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #4 on: July 15, 2004, 12:17:37 AM »
Well, from the data I have gotten on the dyno program I got, the gains are minimal, and if you change rockers ratios, make sure you check that the pushrods don't hit the head, as the diff ratio will move the pushrod closer to the outboard side of the pushrod hole.

read the post about improving low end toqrue, I listed several things that need to be checked if the rockers and / or ratio are swapped.  You can decide if you want ot check it or not, as another member has claimed it is not necesary.  I checked all this on my engine when I went with roller rockers, as it made sense to me, and was highly recommended by both comp cams AND some people who have used them in the past.  I did have some issues to clear up that would have killed the engine if I hadn't.
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Offline Slanted_Mind

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #5 on: July 15, 2004, 02:12:50 PM »
Thanks for the info guys.  Looks like I will be saving $400 :)  Will have to look into the rockers and cam...for future mods.  By then, I will probably just supercharge it though ;D

-SM
1978 W150 Ex Cab 360 2bbl/727/NP203/D44-8.25 For Sale
1987 D150  225/904/8.25  Not even close to stock
2000 Ram 1500 4x4 360/46RE/D44-9.25

Offline Sneezer

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #6 on: July 15, 2004, 05:01:51 PM »
You can also try porting and polishing the stock kegger manifold. A lot of people have experienced some good low end gains after modding it. While it is off pick up an aluminum belly pan to solve the common blown plenum pan gasket problem. You could also relocate the IAT sensor from the manifold to the intake tube. Not much of a gain, but anything helps. Adjust your TPS sensor to 0.72v on your TB. You could also try your hand at porting and polishing the TB. Another mod is a 180 t-stat if not already done. These magnum engines respond better to the cooler t-stat than the stock 195. Replace your plugs with Autolite 3923s. These plugs run a bit cooler than stock, most people have reported good results with them. They seem to be one of the best matches to these Magnum engines. Try an MSD 6AL ignition and BlasterSS coil to get the most out of your ignition system. Accel cap and rotor too while you are at it. The MSD is CARB approved as well. You can also pull off the clutch fan and replace with a good electric fan setup. Viper fans work well, best is a fan of a 93-98 Lincoln Mark VIII. Both are 2 speed fans, max cfm at high speed is over 4000. The Lincoln will require a high capacity alternator though as the fan draws almost 100 amps at startup. Transgo shift kit for the transmission will help firm up your shifts. I am pretty certain they make one for the 46RE. Change your gearing to 3.92 or 4.11. Will be better at lower speeds but you will have higher rpms at highway speeds. That is about all I can think of for now.

New rocker/rollers and cam would also help, but not sure how that would affect your emissions.

Offline Charger92

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Re:Shorty Headers worth it for a 360 Mag?
« Reply #7 on: July 15, 2004, 05:19:45 PM »
I have the 5.2Magnum and did some of what Sneezer is saying with good results. I picked my info off of the speedtweeks website.
I also have shorty JBA's going to single 3" free flow and found it gained a bit. I still run stock gear 3.23's and tire size she wouln't spin em off the line but my second gear chirp is there, just leaving OD off.
Once I change gears and tire size my low end should be good. Every bit helps.
1992 Ramcharger 4x4, MPFI 318 magnum, 94,000 original km's, K&N, MSD wires, JBA s/s ceramic coated headers, Complete mandrel s/s exhaust, Single 3" Magnaflow muffler & Cat, KYB gas shocks, Bridgestone AT Duelers, All synthetic oils, Basically all stock for now! The Very Clean & Muscular Look!

Offline CruPlaya

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Re:Shorty Headers worth it for a 360 Mag?
« Reply #8 on: July 17, 2004, 07:14:04 PM »
For low end, your best bet is long headers, if they are smog legal.  Most headers will give you an improvement, but shorty headers are designed specifically to give improved performance at higher rpms.  Long headers are designed to give improved performance at lower rpms.  But be careful with headers in general, and make sure to insulate them, or otherwise you could give up a significant amount of your potential power gains by raising the temperature of your engine and especially the air coming in.
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Offline mopowered

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #9 on: July 17, 2004, 07:43:40 PM »
Don't give up on the shortys just yet - I have two '96 Rams - both w/the Magnum 360.  On one I have upgraded to the performance computer, the R/T camshaft, K&N FIPK, MSD coil/wires/ignition, underdrive pulleys, MPI single-plane intake, hogged TB, shorty headers, removed the cat, 3-in cat-back exhaust (and lots more I excluded from this list).  After all these mods, the shorty headers were the best improvement in both HP and Torque down low (along w/the MP computer).  You can buy the shortys new off ebay for $195 - worth every penny in my opinion.

Offline Sneezer

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RE: Shorty Headers worth it for a 360 Mag?
« Reply #10 on: July 21, 2004, 03:54:53 PM »
If you go with the 1.7 RR, you will need to either replace your valve covers with the Mopar cast aluminum ones or modify the baffles in the stock ones. Stock are too short for the increased height of the 1.7s and will hit the top of the baffle. You can use a piece of 2x4 to pound it out a little. The cast aluminum ones are higher and thus do not have this issue.

Alternately you can check with www.socaldakota.com. They are selling some really nice billet valve covers for $345. A little pricey but are perfect for engines with adjustable RRs, since you can just remove the top to adjust them and not remove the entire valve cover.