Milling magnum heads

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pjc360

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how much would have to be taken off iron magnum heads to gain 9.5:1 compression?
I was thinking that having .030 shaved off the heads and running a .028 thick head gasket would net at least 9.5:1 or maybe even 9.7:1.
Reason I'm asking is I am trying to figure out a way to squeeze some more power out of my 300hp crate 360 magnum.
I'm running this engine in a 91 short bed half ton 4x4 truck.
I'm running a 4 inch skyjacker all spring lift on this truck with 33/12.50/15 tires on 15x10 wheels.
I was running 3.55s forever and finally had the time and the funds to re-gear it to 4.56s.
And that made a pretty big difference, but it wasn't as big of a difference as I was expecting.
I'm trying to figure out a cheap way to get more power and everyone says get rid of the tiny camshaft that's in this engine.
But in order to run a good sized camshaft I'll need to increase the compression that way I'm not losing a lot of low end torque which this truck really needs being bigger with bigger tires.
The camshaft I am considering running is a Hughes ser2226aln.
Which is 222/226 @ 50 with .549 intake lift and .555 exhaust lift with a 110 lsa.
I've been told if I installed this cam without increasing compression I'd lose a lot of bottom end.
And that with this cam I'm going
To want at least 9.5:1
I was thinking while I had the heads off having them milled if I decide to go that route that I would also have the larger 2.02 intake valves thrown in and have a mild port and polish job on them to increase some air flow.
I know what I'm going to spend in parts and labor and my question is how much more power do you think that's going to be? Running the Hughes 2226 cam with the larger 2.02 intake valves with a mild port and polish job done on them and increased compression from 9.0:1 to 9.5:1 or slightly higher then 9.5:1.
I was thinking that should be worth at least 50-60 hp and maybe 30-50 ft lbs of torque.
I know the hp and torque on these engines is normally higher then what they are rated.
I know someone who dynoed a 300hp crate 360 magnum just like mine that he had put Hedders and msd ignition and demon carb and it made 319hp and 424 ft lbs.
So if I could be around 375hp and 450-460 ft lbs with the bigger Hughes 2226 cam and the bigger 2.02
Valves and a increased compression then it would be worth it to me to spend the money.
 
Dude, honestly, a half a point of compression is worth less than a turd as far as power is concerned. 1 FULL point is worth maybe 10-12hp at this stage in the game. Also, bigger valves will NOT help your cause as they mainly benefit high RPM applications, the 1.92 is better for torque and street applications due to velocity. 2.02 WILL probably loose grunt, which obviously know you need. Unless you live at 5000-7000rpm all the time, driving around in first gear only.

Get with a cam company and carefully select a cam. If you have an automatic get with a converter company like PTC, Dynamic, Ultimate, etc. and have them make your one up. No off the shelf stuff. This is BY FAR the most OVERLOOKED way to get the absolute BEST out of your combination, the rest is pissing in the wind.

Everyday, people spend $15,000 on an engine, then a $150 B&M fartshot converter to tie it all in.... *heavy sigh*

Cam, converter and gears must work together!

In the end a 360 is good for 400ft/lbs and maybe 350hp. You can move these numbers around a little with cam selections, but it's the truth.

Pay your money, take your chances. Been there done that.
 
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If you can't swing a custom converter, grab the Hughes XTM. I have one in my suburban with a Vortec 5.7L. WOW what a puller!! It damn near rips my transfer case boot off of the mount every time I hit the gas more than gingerly from a dead stop with 33's and 4.10's.. Feels like another 100ft/lbs, compared to the Hughes Tow Master I had in it before. F***!
 
How do you know you don't have 9.5 already? Have you measured it?

Your question is impossible to answer, unless you know what your compression is NOW.
 
400hp and over 420ft lbs is pretty easy with Iron Magnum heads on a stock bottom end Magnum with the right cam intake and carburetion with headers.
Problem is, as mentioned you are talking more about top end with your thoughts on parts selection.

IMHO you want to get a torque cam which pays more attention to duration and seat time instead of lift and valve size.
I'm running right at 350hp with an Edelbrock dual plane and 600 carb with 1 5/8 tubes and 3" collectors with the base 9:1 compression of the Magnum.
A 780 or 800 Holley on top of the Magnum airgap intake is worth 40-50 more horses, but I'm not in it for max power.
My cam is designed for torque and is 214/224 @50 with a .512 lift on a 110 lobe center with the Hughes spring kit and stock 1.92 valves.
You might want to ask Evan from Mopar Fuel Injected Magnum Engine Swaps. MAGNUM MOPAR what he can do for some good springs and retainers that allow a bit more lift for those heads.

His username on here is magnummopar
 
I haven't measured the compression of this engine.
But the paper work that came with the engine states it has 9.0:1 compression ratio.
I already have gears, 4.56s and it did help no doubht, but I guess I was expecting a little more then what I got.
So what type of converter should I be looking for? I do have an automatic it's the non lock up A-518.
And it has been re-built, transmission was the first thing I did after installing the 300hp 360 magnum.
So do I want a higher stall converter or a lower stall converter?
And what would be a good camshaft for what im trying to do?
I obviously don't want a high rpm
Screamer, I want as much torque as possible because this is a lifted 5000 pound truck with big tires.
I'm already running Hedman 1 5/8 Hedders into dual 2 1/4 inch exhaust with an H pipe.
I'm running the dual plane m1 intake that came with the engine and a 2 inch 4 hole aluminum carburetor spacer.
That carburetor spacer helped
With torque a bunch, I'm running a quick fuel super street series 680cfm vaccum secondary carburetor.
I'm running a mopar performance distributor put together by don at fbo systems.
I'm running 16 degrees of initial timing and 34 degrees total timing all in by 3000 rpm.
I was thinking there might be more power hiding in the all in distributor timing now that I'm geared better with 4.56s. I was thinking having the timing all in by 2500 rpm might be better.
I'm running a crane cams hi-6 cd ignition with the crane cams lx91 coil.
Ngk plugs gapped at .050.
I don't know much about cam shafts and what sizes do what.
So that's why I'm asking.
 
Hummmm, I do remember the Dodge Crafstman Truck series in NASCAR limited the engines ratio to 9.0-1 but yet they still made over 700hp.

So tell me, why do you need to gain some compression again?

IF everyone is saying just change the cam, then perhaps just perhaps there right. Just perhaps.....
 
pjc360 said:
how much would have to be taken off iron magnum heads to gain 9.5:1 compression?
I was thinking that having .030 shaved off the heads and running a .028 thick head gasket would net at least 9.5:1 or maybe even 9.7:1.
Reason I'm asking is I am trying to figure out a way to squeeze some more power out of my 300hp crate 360 magnum.
I'm running this engine in a 91 short bed half ton 4x4 truck

I'm running a 4 inch skyjacker all spring lift on this truck with 33/12.50/15 tires on 15x10 wheels.
I was running 3.55s forever and finally had the time and the funds to re-gear it to 4.56s.
And that made a pretty big difference, but it wasn't as big of a difference as I was expecting.
I'm trying to figure out a cheap way to get more power and everyone says get rid of the tiny camshaft that's in this engine.
But in order to run a good sized camshaft I'll need to increase the compression that way I'm not losing a lot of low end torque which this truck really needs being bigger with bigger tires.
The camshaft I am considering running is a Hughes ser2226aln.
Which is 222/226 @ 50 with .549 intake lift and .555 exhaust lift with a 110 lsa.
I've been told if I installed this cam without increasing compression I'd lose a lot of bottom end.
And that with this cam I'm going
To want at least 9.5:1
I was thinking while I had the heads off having them milled if I decide to go that route that I would also have the larger 2.02 intake valves thrown in and have a mild port and polish job on them to increase some air flow.
I know what I'm going to spend in parts and labor and my question is how much more power do you think that's going to be? Running the Hughes 2226 cam with the larger 2.02 intake valves with a mild port and polish job done on them and increased compression from 9.0:1 to 9.5:1 or slightly higher then 9.5:1.
I was thinking that should be worth at least 50-60 hp and maybe 30-50 ft lbs of torque.
I know the hp and torque on these engines is normally higher then what they are rated.
I know someone who dynoed a 300hp crate 360 magnum just like mine that he had put Hedders and msd ignition and demon carb and it made 319hp and 424 ft lbs.
So if I could be around 375hp and 450-460 ft lbs with the bigger Hughes 2226 cam and the bigger 2.02
Valves and a increased compression then it would be worth it to me to spend the money.
Click to expand...
Personally ,post 2 nailed it.... Having done a Magnum 5.9,been around 4x truck hot rodders,Here's what I would do,to get it right ,the first time. That 22/26 Hughes grind isn't gonna pull until 2000-2500...(I run a 229/233 similar grind forget good torque until 3000 + rpm....,you need mid range torque,not mid to upper range h.p.(I'm thinking:210-215 @ .050, depending on intake,a 110-112 lobe center cam Call Hughes,(or whoever you like...) actually ask for a cam recommendation.I would use the 1110 spring /matched retainer kit. Buy a good timing chain,degree it correctly. Hughes makes some really nice converters.) Magnums make chunkloads of torque,in the low end & mid range, installing a two sizes too big a cam,makes it harder to drive. Been there,done that.(Personally ,I would leave the stock heads alone,if good. If cracked,E/Q 1.92 replacement heads ,are capable of 450 horsepower,no porting,& can be bought assembled 1000-1200 assembled,this is what I did.
 
Would the ed heads make much of an improvement on a torque build like this one?
 
pjc360
We have been building heavy large tire 4x4's with magnums since 1998. We have EQ's for best deal on internet, we have several cams for 5000 # trucks and jeeps. 212@50 .525 lift 110 would bee perfect and with that cam and your gearing the factory converter will stall at 2k which is where you want it. PM for our shop # or find us on the web magnummopar. Evan
 
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pjc360 said:
So what type of converter should I be looking for? I do have an automatic it's the non lock up A-518.
And it has been re-built, transmission was the first thing I did after installing the 300hp 360 magnum.
So do I want a higher stall converter or a lower stall converter?
And what would be a good camshaft for what im trying to do?
Click to expand...


Stall is dictated by the cam specs. Get your cam right then look into conveters.
 
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