Magnum RHS Heads horsepower gain??

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dustoff440

dustoff440

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what kind of hp gain would you get on a mild 360 magnum by installing out of the box RHS iron heads??? I saw a dyno test with Edelbrocks and they were worth 50 hp
 
I'm not the expert but it seems to me the power gain from just a head swap is going to be far less than what the heads make possible with the right cam and other parts.
 
Idaho said:
I'm not the expert but it seems to me the power gain from just a head swap is going to be far less than what the heads make possible with the right cam and other parts.
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OK heres the combo

360 mag
crosswind dual plane
otb 650 double pumper
int 498 ex 512. int 276 exh 286 lsa 112
stock 9.1 to 1 cr
hooker 1 7/8 headers
mp dizzy
msd 6al
stock bottom end
3,91 gears
3500 stall converter
904 with reverse body

seen the same combo dyno 375 hp and 400 lbs tq (flywheel)

do you think the rhs heads OTB would add 40 hp?
 
If you already have magnum heads and you're sticking with the Crosswind I doubt you'll see anywhere near 40hp. The intake is already a limiter. I'll add - Not seeing the head tests, IMO if the RPMs were down 50hp to the RHS, there were issues with either the condition of the RPMs when first bolted on (they were'nt corrected by a competant shop) or the combo wasn't designed right and the RPMs were the wrong head to start with.
 
I think hes saying the rpms were 50hp better then stock magnums on a dyno test. not 50hp better then the rhs heads
 
The RHS flow slightly better than Eddys on every flow test I've seen. More cam & comp would get you similar results as the head swap for less dollars but be less streetable, I'd go with the head swap.
 
So can anyone give a rough breakdown for horsepower gains?
Stock 5.9 upgrade heads only.
Add cam upgrade.
Add intake/carb.
Add headers/exhaust.
The comp cams simulator does this but not sure how accurate that is and I'm not sure how to input a stock cam.
 
So can anyone give a rough breakdown for horsepower gains?
Stock 5.9 upgrade heads only 20-30hp give or take the assembly - I think Indy is the only place to get them now too, and they come bare. So if a performance shop gets them, does a good modern valve job,and uses the right parts I don;t think 30hp is far fetched with no other changes.

Add cam upgrade. - Need to have a cam design to even consider and it's dependant on the intake, heads, and exh manifolding choices.

Add intake/carb. - - Another 15 - 25hp with intake alone. Carb's fine IMO

Add headers/exhaust. - If you have manifolds now - an easy 25-30hp with headers and decent 2 1/2" pipes w/good mufflers. If your exhaust is stock now, closer to 10-15hp.

The comp cams simulator does this but not sure how accurate that is and I'm not sure how to input a stock cam.
 
HP gains will increase with the performance parts added. As the level of perfoance goes up, so does the HP spread between the part being tested, in this case, heads.
 
moper said:
So can anyone give a rough breakdown for horsepower gains?
Stock 5.9 upgrade heads only 20-30hp give or take the assembly - I think Indy is the only place to get them now too, and they come bare. So if a performance shop gets them, does a good modern valve job,and uses the right parts I don;t think 30hp is far fetched with no other changes.

Add cam upgrade. - Need to have a cam design to even consider and it's dependant on the intake, heads, and exh manifolding choices.

Add intake/carb. - - Another 15 - 25hp with intake alone. Carb's fine IMO

Add headers/exhaust. - If you have manifolds now - an easy 25-30hp with headers and decent 2 1/2" pipes w/good mufflers. If your exhaust is stock now, closer to 10-15hp.

The comp cams simulator does this but not sure how accurate that is and I'm not sure how to input a stock cam.
Click to expand...

It's all so easy until you get to the cam. The cam... The stinky cam choice... Hurts my brain #-o
 
Whats your goal with the car ? LXGuys Dart is running 11s with a pretty mild 360 Magnum. He has EQ heads a small cam and a RPM Air Gap
 
AdamR said:
Whats your goal with the car ? LXGuys Dart is running 11s with a pretty mild 360 Magnum. He has EQ heads a small cam and a RPM Air Gap
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I likely should not be getting into it on dustoff's thread. I've put up a couple threads already and got decent feedback from people including LXguy. I've done a fair bit of reading on the subject as well but found there's a lot of differing opinion - and hot tempers to go with the opinions.

Eventually I'll have to trust someone with the choice when I put the engine together and it will likely turn out fine (at least that's what I'm telling myself). It just would be nice if things were more cut and dried. Camshaft choice seems to be anything but.
 
I can tell you this.Stock heads,Crower grind: 284 advertised,224@.050.112 lobe centers,.491 lift..21" vacuum@800.Sounds,like a stock 340 grind.No chance to drive yet,car blown apart,for paint.
 
AdamR said:
Whats your goal with the car ? LXGuys Dart is running 11s with a pretty mild 360 Magnum. He has EQ heads a small cam and a RPM Air Gap
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Street car, I'm hoping for 11.90's thru the mufflers with a 150 shot of gas. I'm thinking that after drag/friction that I will have 425 hp or so at the wheels
 
dustoff440 said:
Street car, I'm hoping for 11.90's thru the mufflers with a 150 shot of gas. I'm thinking that after drag/friction that I will have 425 hp or so at the wheels
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You shouldnt need nitrous for that.

Heres LXGuys combo. I would ask him if he knows the specs on the cam.

Engine:
1999 5.9 Magnum engine.
Hughes Iron Ram heads (drilled for LA intakes)
RPM Air Gap intake
Quick Fuel 750 carburetor
Mallory Electronic ignition (with two step, rev limit, spark retard, etc)
Kevko oil pan
Mopar valve covers
Custom Comp hydraulic roller cam (nice sound, but VERY streetable)
Harland sharp rocker arms
Hooker Comp headers with Darkside ceramic coating.
TTI X-pipe with Ultraflow mufflers into dumps ( have TTI tailpipes also)
New radiator and electric fan (have original radiator/fan setup)
Carter mechanical fuel pump
Cloyes billet double roller timing chain

This engine made 332 rwhp on a Dynojet dyno.

Drivetrain:
904 Transmission
Basically every trick from the A&A catalog except it has a stock drum (I have over $2000 in parts in this transmission).
A&A manual transbrake valve body
Cast aluminum pan
AN fittings and B&M stacked plate cooler
Ultimate Converter Concepts 9” torque converter (Streetable 3500 stall) ($900 new)
Dynotech custom Aluminum racing driveshaft
A body 8.75 rear with Moser Axles, Detroit Locker and Motive 3.91 gear.
 
425 at the wheels should run 11.00 or better in a 3200# or lighter car.
 
From LXGuy's thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=106857

If I had it to do over again, I'd go with less lift on the cam. Its got (EDIT .544, and that's just too much. It causes valvetrain issues, puts a hurting on the springs, and I cant get the cool Hughes shaft rockers because they're 1.65 ratio. I bet if I had .525 lift the power would be exactly the same.

I would also have the heads machined for better springs than the ones Hughes provides (though to be fair I didn't realize they had to be machined for that when I bought them).
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The cam is a custom grind hydraulic roller. Heads are as-cast from EQ or wherever Hughes gets them. No porting, no milling. I've got to say, I've been pretty impressed by them-especially for the price.
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Cam is 224/230 @ .050. The stall is right around 3800. I've only been launching at 2400.
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IDK what my RHS headed stock 5.9 magnum makes with the 525 lift 226 dur 108 LSA cam it has, but I like it! A guess is 425 at the crank. Burnouts at will.
 
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