How much milled off heads to raise compression

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You are both right, TMM and YR. You can run more compression on a aluminum head engine because the aluminum head flex's more, causing 3 cc's more of chamber. I put my go-pro hero 8 under my hood and when floored under load, you can see the head bulge up under the compression stroke above the cylinder of power stroke if you play the camera in super slow motion to the measurable of 3cc's. That is why aluminum heads allow more initial compression, though they give it right back throughout the RPM.
that's at full throttle but what about at idle when you go to turn it off and it goes knock knock knock....
 
I'll take that as gospel then and consider all the information out there as hogwash. Why the heck does everybody waste time and money to use aluminum heads if only to save a little weight and may be easier to modify?


That’s why. Exactly why. They don’t make any more power. Also, consider tooling. When machining aluminum it’s much easier on tooling than cast iron. So the OEM’s love to use aluminum because it saves on drills, taps and other tooling.

The number one reason why guys can’t run compression is coolant temp. 180 should be the maximum coolant temp on any performance engine. Ever.

Guys running above that are wasting power and causing issues like run on.
 
That’s why. Exactly why. They don’t make any more power. Also, consider tooling. When machining aluminum it’s much easier on tooling than cast iron. So the OEM’s love to use aluminum because it saves on drills, taps and other tooling.

The number one reason why guys can’t run compression is coolant temp. 180 should be the maximum coolant temp on any performance engine. Ever.

Guys running above that are wasting power and causing issues like run on.
I always run a 160 t-stat in my rods, but I'm odd...
 
Yeah new pistons sounds good but the frig factor is high. Would they have to be custom made or does someone make them already? The cam I want
Calls for 10.5 to one and now have
9 to one, if I’m lucky. BTW does nitrous work better with high or low compression??

Milling for compression certainly can be and has been done. A lot in fact. I've done it myself...however, I don't recommend it. I've done it really recently too, but on a slant six. That's a little different bird, though, as the head sits straight and the manifolds bolt to the side of the head.

If you mill for compression, for 1 compression ratio, you're going to be in the .080" neighborhood. Stacking that up on a feeler gauge doesn't look like much, but what happens is, it changes the angle at which the intake manifold sits on the engine and will require the intake to be milled to match in order for the bolt holes and ports to line up and for it to seal properly. So, in reality, the friggin will probably be close to the same, because machine shops charge more to cut more amounts off, plus, you have to have the intake milled to match, so there's your piston cost.

Besides all "that", the stock compression ratio on the Magnums is over 9:1. The difference between compression ratios, say from 9:1 to 10:1 is only about a 3% power increase. If it was mine, I'd leave it alone.
 
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That means you can’t tune. That’s when that happens. You should really pay someone to do your tune up for you.
I didn't even know you were still part of this forum.... I unlocked this page and there you are with the same put down/self-promotion crap ola....
My car is in perfect tune...
Internet hero... In 3-2-1.....
 
that's at full throttle but what about at idle when you go to turn it off and it goes knock knock knock....
And I thought you were a smart guy. Run on or dieseling can be caused by hot spots like detonation happens but not by low octane gas. Your idle can be too high causing it to diesel. What are "anti dieseling solenoids" for? How about detonation sensors on newer engines that retard the timing to prevent engine ping?
 
Let’s say the stock magnum heads flow
220@.550 and they were ported to 300cfm. Do you think that this situation is workable?
If theydo flow 300 cfm stock ported heads over ebelbrock I will use them
Is an additional 70 cfm on stock ported
Magnum a stretch ???
 
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You are both right, TMM and YR. You can run more compression on a aluminum head engine because the aluminum head flex's more, causing 3 cc's more of chamber. I put my go-pro hero 8 under my hood and when floored under load, you can see the head bulge up under the compression stroke above the cylinder of power stroke if you play the camera in super slow motion to the measurable of 3cc's. That is why aluminum heads allow more initial compression, though they give it right back throughout the RPM.

P.S. - I always run a .050 head gasket to accommodate the flexing so no leaks


:D
Should not this have been posted on April 1? That is when I will again post about my flexi-stroker crankshaft that increases engine stroke as rpm increases.
 
Should not this have been posted on April 1? That is when I will again post about my flexi-stroker crankshaft that increases engine stroke as rpm increases.
:rofl::rofl:
 
Should not this have been posted on April 1? That is when I will again post about my flexi-stroker crankshaft that increases engine stroke as rpm increases.

One key to really taking advantage of that is to run more deck clearance so when the crank starts adding cubes, it’s not limited by the pistons touching the heads too early in the flex stage.

It’s not only variable displacement, but the byproduct of that is the variable CR.

The real April fools day thing I noticed in this thread was the 300cfm stock magnum heads.
 
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One key to really taking advantage of that is to run more deck clearance so when the crank starts adding cubes, it’s not limited by touching the heads too early in the flex stage.

It’s not only variable displacement, but the byproduct of that is the variable CR.

The real April fools day thing I noticed in this thread was the 300cfm stock magnum heads.
Does Rhoads make lifters for this application?
 
Should not this have been posted on April 1? That is when I will again post about my flexi-stroker crankshaft that increases engine stroke as rpm increases.
LOL... I couldn't refrain :D

how many read it and were afraid to comment, not sure if it was true or not :D
 
And I thought you were a smart guy. Run on or dieseling can be caused by hot spots like detonation happens but not by low octane gas. Your idle can be too high causing it to diesel. What are "anti dieseling solenoids" for? How about detonation sensors on newer engines that retard the timing to prevent engine ping?
Not smart just handsome! LOL...
At 11 to 1 I went all over the place with adjusting carbs timing different carbs different adjustments different heads different head gaskets and so forth... I do idle just a tad higher than most as I really don't like it chopping really hard.. one inevitable factor always seems to work and that's adding just a tidbit of octane and zero problems. not that I have any serious problems when I don't use a little octane of course I can always shut it off against the clutch a little bit but I just prefer my engine to shut down nice and quick on its own... The aluminum heads didn't solve the problem... I bought a bottle of torco fuel octane booster and we're going to give that a little whirl this summer.. it just needs the slightest bit of octane boost to make the run-on problem go away. Right now I had maybe one gallon to a tank full and no problems. Again no big problems here just a little run on without some octane. Af gauge reads perfect at idle cruise and full throttle and plugs look pretty good...
 
Not smart just handsome! LOL...
At 11 to 1 I went all over the place with adjusting carbs timing different carbs different adjustments different heads different head gaskets and so forth... I do idle just a tad higher than most as I really don't like it chopping really hard.. one inevitable factor always seems to work and that's adding just a tidbit of octane and zero problems. not that I have any serious problems when I don't use a little octane of course I can always shut it off against the clutch a little bit but I just prefer my engine to shut down nice and quick on its own... The aluminum heads didn't solve the problem... I bought a bottle of torco fuel octane booster and we're going to give that a little whirl this summer.. it just needs the slightest bit of octane boost to make the run-on problem go away. Right now I had maybe one gallon to a tank full and no problems. Again no big problems here just a little run on without some octane. Af gauge reads perfect at idle cruise and full throttle and plugs look pretty good...



LOL. Like I said, fix your tune up. Or don’t. But that’s YOUR issue.
 
April the First is here so we can have some fun!,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,POST NUMBER #43!!!

Back in the 60's Mother Mopar made high compression engines and then the 70's came...
Pistons were lowered 'down the hole' a 100 thousanths maybe more!
200 hp Bigblocks that couldn't get out of their own way...:realcrazy::realcrazy::realcrazy:

50 years on we are still talking about it and nothing has changed except for expensive CRAP GAS!

We now know, that all those sexy 'pop-up' pistons were the worst thing ever!

So where are we now?
Flat tops at ZERO deck and the rest just falls into place...:drama::mob:

They knew this back in the fifties with 'flat top' pistoned 8 to 1 hemi engines...:thankyou:
 
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Would you really put Nitrous in a worn out 'cast piston', 'cast iron' ringed 360???:wtf:

Why did I waste all that money on a rebore with very DEAR FORGED pistons, trick rods, steel crank and MOLY rings...:mob::realcrazy::poke::BangHead::(:rolleyes::soapbox:

FOUR bolt main caps, expensive chamfered bearings, studs and a girdle...:wtf::mad::realcrazy::(:(:(

If only I had known about RACE FUEL TOO...:rofl:



APRIL FOOL,
ONLY KIDDING, I DID KNOW ABOUT RACE FUEL, just couldn't afford it at £20 a gallon.
 
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You can usually mill the heads quite a bit as long as you take the proper amount off this intake. I'm guessing later heads may be thinner but my ported "J" heads when I had a small block were down in the 60-62cc range after getting chopped and worked quite well on my 360. I'd see if you can find someone who's played with later model stuff. One of the head porter's out there. They typically know how thick decks are, etc.
 
I've milled .050 off heads with no fitment problem...
Four bolt mains on a small block Mopar... LOL...
 
LOL... I couldn't refrain :D

how many read it and were afraid to comment, not sure if it was true or not :D
Well one guy definitely missed it lol.

To the op imo if you are on a budget then I would put it together basically stock with a cam, tune it, and hit with a 100 shot and not worry. If you are building something with more money than I would put some into the heads and some good forged pistons and still hit with a 100ish shot. One thing the "nitrous purging guru" (I just couldn't resist lol) left out is when nitrous company's are saying it's safe to hit stock pistons with a 150 shot they are talking about a stock engine with low hp levels. Build the engine to higher hp levels and now you are asking cast pistons (and any other stock components) to handle 550 plus hp and you better be sharp on the tune, keep the rpms in check and have a plan B.
 
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As far as the aluminum vs cast iron head debate engine masters episode 57 imo is a must watch.
 
Well one guy definitely missed it lol.

To the op imo if you are on a budget then I would put it together basically stock with a cam, tune it, and hit with a 100 shot and not worry. If you are building something with more money than I would put some into the heads and some good forged pistons and still hit with a 100ish shot. One thing the "nitrous purging guru" (I just couldn't resist lol) left out is when nitrous company's are saying it's safe to hit stock pistons with a 150 shot they are talking about a stock engine with low hp levels. Build the engine to higher hp levels and now you are asking cast pistons (and any other stock components) to handle 550 plus hp and you better be sharp on the tune, keep the rpms in check and have a plan B.
I must have forgot all this firsthand nitrous knowledge of yours? Please regale us again of all the times you've used it...
 
I must have forgot all this firsthand nitrous knowledge of yours? Please regale us again of all the times you've used it...
Do you not understand the correlation between the hp level and load on an engine or are you just trying to be cute?. Judging from the above post where you talk about you're handsomeness I'm guessing it's the latter. :lol:
 
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