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452 heads

  
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452 heads

 
hockeydad1189 hockeydad1189
User | Posts: 69 | Joined: 08/07
Posted: 06/15/10
11:37 AM

hi i have two sets of 452  heads both stock valves, springs,the only difference is one set has been milled about .050 .will i see a big increase in compression with these heads, they will be on 8.5 to 1 440 ,also would there be any increse in tourque and hp if so about how much i also will be using .020 steel head gaskets  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
12:10 PM

It depends on what those 8.5:1 pistons use as a combustion chamber reference. If they use a closed chamber, then you might end up with less than 8.5 because the 452s are open chamber. even .050" will not make them as small as closed chamber heads. So, it's all dependant upon what heads the pistons are supposed to have 8.5 with. Also, .050" is a good bit to mill a head. You'll need to have the intake milled to match, or it won't seal properly.  
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heyoldguy heyoldguy
User | Posts: 64 | Joined: 10/09
Posted: 06/15/10
01:20 PM

Let us see if we can actually answer the question.

If you mill 452 heads .050" you will reduce the combustion chambers approximately 11 cc. If all you do is mill the heads, and do not change the head gasket thickness, this will result in upping the compression ratio to 9.2:1. For every 1 point gain in compression ratio you gain approximately 4% in horsepower. Therefore, if you originally had 350 HP before you milled the heads, you will now have 360 HP.

If you mill the heads .050" and change from a .040" gasket to a .020" gasket you will change from 8.5:1 to 9.6:1 and a 350 HP engine will now produce 365 HP.

Now none of these horsepower figures are guaranteed, they are only reasonable approximations.

If your heads were milled by a competent machine shop they will know to mill .0123" off the intake manifold surface for every .010" milled off the head gasket surface. Let's pray they were competent or "Stroker" will be correct and the manifold ain't gonna fit.  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
03:45 PM

How do you know all that? Without knowing which head the piston is supposed to acheive 8.5:1, you're just guessing at best. All that hooha sounds great, but without knowing his baseline, which you do not, it's all up in the air.  
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dubber123 dubber123
New User | Posts: 19 | Joined: 06/10
Posted: 06/15/10
04:47 PM

They never made a 8.5:1 rated 440 with anything other than open chamber heads to my knowledge.  I would have to assume that makes heyoldguys calculations correct.   11cc's is a good bit to reduce a chamber, and I bet it's a difference you can feel for sure.  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
04:56 PM

Agreed, but the OP didn't say they were factory pistons. He didn't say they weren't. The 440 has been out of production a long time other than a crate engine so, there could be anything in there. Rather than assume, and answer with a possible incorrect answer, I was wanting more info is all. Without piston top CC, it's imposible to calculate correct compression ratio.  
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.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
04:59 PM

He probably is right on the money. He usually is. He's a sharp old guy. LOL I wasn't trying to be malicious, I was simply saying compression ratio is something I would wanna be dead sure about, because the aftermarket did make lots of piston choices.  
____________________

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heyoldguy heyoldguy
User | Posts: 64 | Joined: 10/09
Posted: 06/15/10
05:05 PM

Stroker I did not guess, he gave me a baseline to work with: 440, 8.5:1, 452 heads milled .050" & .020 thick head gasket. At this point in time I have no reason to dispute his claim as to what he has. If he has 452 heads and mills them .050" he will decrease the combustion chamber about 11 cc and that will increase his compression and horsepower to approximately the amount I have stated.

He did not asked me what pistons he had. He asked me what his compression ratio would change if he had 8.5:1.

How do I know all that? I'm pretty damn good at building wedges. I have two in my garage right now. One at 451 ci, single dominator, 93 octane 775 HP, no bottle and no boost. And the other is 500 ci, single dominator, all motor, 928 HP. I learned a teeny, weeny little bit before I could do that.  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
05:18 PM

Again, I wasn't being smart. I know full well you're extremely knowledgable. I wasn't disputing that at all...I think you misunderstood. Perhaps I didn't convey it right. All I meant was he said he had 8.5 and two sets of the open chamber heads. He didn't say either set came on the engine, therefore, in my mind, that puts the 8.5 in question. It just sounded a bit cloudy to me, that's all.  
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heyoldguy heyoldguy
User | Posts: 64 | Joined: 10/09
Posted: 06/15/10
05:53 PM

What he actually has is '78 440 with 92cc Stage V iron heads as stated in another post. The Vs flow better but not a gigantic amount. If he switches to the milled 452s he gains compression and looses flow. It's probably a wash. I would choose flow over compression. Take the milled 452s and home port them like Tech Ed Dave Young shows in the August issue of Mopar Muscle Mag (just out by the way) and he'll have his compression AND some more flow. The tools don't cost much and it makes a big difference.  

.71RedneckStroker_ .71RedneckStroker_
Guru | Posts: 848 | Joined: 11/09
Posted: 06/15/10
05:56 PM

That makes sense. See, there was sumthin missin, dangit. I didn't know about the other post. lol  
____________________

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drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 06/15/10
06:44 PM

452's compared to closed chambered 516's.
My old 440 had a pair of closed chambered 516's, yuck! They were ported and polished with stock valves.
Ran a best ever 12.64 at 108mph in my street B body.
Switched up to a fresh set of 452's. Ported, polished, larger valves, and the heads cut .060 + I used thin head gaskets. Everything else remained the same, including the flat top pistons which were sitting something like .080 in the hole. This was a factory .040 over short block, rebuilt by Chrysler with a ton of miles, with a Mopar .509 Hydraulic cam.
Anyway, first pass out with the new heads the car went 11.96 at 114mph.
Talk about a happy camper!
These heads with all the work, were less than half the money of a set of Eddy's with similar results.  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 06/15/10
06:45 PM

452's?  

drmopar drmopar
Guru | Posts: 1445 | Joined: 02/08
Posted: 06/15/10
06:46 PM

452's compared to closed chambered 516's.
My old 440 had a pair of closed chambered 516's, yuck! They were ported and polished with stock valves.
Ran a best ever 12.64 at 108mph in my street B body.
Switched up to a fresh set of 452's. Ported, polished, larger valves, and the heads cut .060 + I used thin head gaskets. Everything else remained the same, including the flat top pistons which were sitting something like .080 in the hole. This was a factory .040 over short block, rebuilt by Chrysler with a ton of miles, with a Mopar .509 Hydraulic cam.
Anyway, first pass out with the new heads the car went 11.96 at 114mph.
Talk about a happy camper!
These heads with all the work, were less than half the money of a set of Eddy's with similar results.  

heyoldguy heyoldguy
User | Posts: 64 | Joined: 10/09
Posted: 06/16/10
07:21 AM

Patience, take your time. 4% here, 5% from this part, 2% from that corner, 6% from this item.

But there is almost nothing to be gained from switching from unported stock head to another unported stock head. Sorry.

The cylinder heads are the door to the bowels, the very guts of your horsepower. If you have the tools and skill you can do them yourself. If no, you have to rely on others. If neither of these is an option you have to buy them.

Slay the dragon yourself or hire a mercenary.  

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