452 heads on a 1965 Wedge ?

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Brooks James

Brooks James

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The heads I have are the original 516 ones that are closed chamber, with flat top no notches.
The factory compression is 10.3 to 1, which I feel will be too high for pump gas

My question is :
To calculate the cr with 452's, do I find the cc's of the heads and subtract the difference,
What I don't know is how many cc's are in a point of compression ??
 
I can do that for you... but you would be better off learning to do it yourself.
I always recommend the calculators at Wallace racing, they work easily and well for me... and he has about a hundred of em.
Trouble is, for ACCURATE results, ACCURATE measurements are required.
(And I would assume the 452s at about 88-90 cc, and I would assume the 426W factory rating for c.r. is optimistic, like most Mopar c.ratios)
 
Yeah, I dug it out,
With 452's and and an eighty thousandths head gasket 9.27 :1

We have 93 octane here, shouldn't be a problem
 
Edit
Just found a forged stroker kit for 426 wedge at Mammoth Racing, has the longer rods (7.1) inches
$2600
 
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You might consider 906 Heads.
Two or three less CC as I recall would
get you near 9.5 Compression

The 906 head flow considerably more
than the 452 in stock form.

You do have to consider the seat issues.
I know 906 heads do not have harden seats.
I do not remember if 452 sometimes or always
have harden seats or not.
 
Details matter.
For giggles, for a .030 over 426W
90 cc head, .039 head gasket, .050 deck...... less than 9 to one.
88cc head, .025 head gasket, 010 deck....... slightly over 10 to one.
75cc head, 039 hg,.050 deck...... 10.16 to one.
75cc head, .025 hg,. 010 deck......11.58 to one.
All above calculated with flattop pistons, with no valve reliefs. Dome, dish, or valve reliefs, are another HUGE variable.
 
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"Somewhere" around 6 to 7 CCs = 1 compression point. If the chamber is round, like a Hemi for instance, that's even less, because when milled, you're removing from the entire outer perimeter of the chamber.
 
If your 65 motor has its original steel shim head gaskets, switching to Fel Pro .039 inch thick gaskets will lower the CR probably close to half a point.

But I doubt the original CR was actually 10.3 to one. If the motor is in the car now and running, I'd drive it and see how it does. My guess it you'll be OK.
 
i used them on a stock 9 to 1 65 383 , cam'd and twin inline fours and full length tube headers . it ran fine and with 2.76 rear gears it would pull to 6k at 120 mph in second gear of the 727 and flat get it with the nose up when i pulled into drive . this was in my 65 custom 880 rag with 130k miles on it .
 
Brooks James said:
My question is :
To calculate the cr with 452's, do I find the cc's of the heads and subtract the difference,
What I don't know is how many cc's are in a point of compression ??
Click to expand...
Compression ratio is the volume of the cylinder sweep divided by the volume of the cylinder head. Nothing more to it.

For what is worth I would never use a an .080" thick head gasket on an engine unless your running a Top Alcohol (Blown) class (which they do).

Easiest way to figure compression ratios is to use the Summit Racing Compression Calculator Compression Calculator

Tom
 
Not quite correct^^^^^.
Comp ratio is: the swept volume of the cyl with the combustion chamber volume added to it divided by the chamber vol.
 
Brooks James said:
The heads I have are the original 516 ones that are closed chamber, with flat top no notches.
The factory compression is 10.3 to 1, which I feel will be too high for pump gas

My question is :
To calculate the cr with 452's, do I find the cc's of the heads and subtract the difference,
What I don't know is how many cc's are in a point of compression ??
Click to expand...
10.3 is NOT TOO MUCH FOR 93 OCTANE. tune it & drive it. If you can't tune it run a octane additive... either way just get it going and see what it does
 
Brooks James said:
The heads I have are the original 516 ones that are closed chamber, with flat top no notches.
The factory compression is 10.3 to 1, which I feel will be too high for pump gas

My question is :
To calculate the cr with 452's, do I find the cc's of the heads and subtract the difference,
What I don't know is how many cc's are in a point of compression ??
Click to expand...

That's not too much compression. Fix your cooling system and learn to tune a carb and distributor. I can run 12:1 on pump gas and iron heads. It's crazy to go less than 10:1 because you are pissing power away. And drivability.
 
Newbomb Turk said:
That's not too much compression. Fix your cooling system and learn to tune a carb and distributor. I can run 12:1 on pump gas and iron heads. It's crazy to go less than 10:1 because you are pissing power away. And drivability.
Click to expand...
amen !
 
Yeah 12:1 on pump gas...& iron heads. Yeah right. That is why we are all doing it........because it works every time.
Every time now I see a post by Newbomb Turk, the needle on my BS meter shakes violently.....
I have had engines with 8.5:1 CR detonate on pump petrol.
There are many factors that can cause detonation, some are 'built in' to the original engine design which limits CR.
Far better to pick a modest CR & be safe; then you are not limiting your ign advance curve [ & losing power ] to try & control detonation.
 
Bewy said:
Yeah 12:1 on pump gas...& iron heads. Yeah right. That is why we are all doing it........because it works every time.
Every time now I see a post by Newbomb Turk, the needle on my BS meter shakes violently.....
I have had engines with 8.5:1 CR detonate on pump petrol.
There are many factors that can cause detonation, some are 'built in' to the original engine design which limits CR.
Far better to pick a modest CR & be safe; then you are not limiting your ign advance curve [ & losing power ] to try & control detonation.
Click to expand...
Newbomb Turk isn't building a run of the mill engine to run 12.1 on pump gas. What he is saying to the op is 10.3 is not too much compression for pump gas 93.
My engine is about 13.1 with most people's pump gas iron head dcr 9.65 it will run on pump gas. I run it on av gas 100 when everyone said atleast 110 and it kicks *** on 100, I however hate pump gas smell so I chose the av gas
 
Bewy said:
Yeah 12:1 on pump gas...& iron heads. Yeah right. That is why we are all doing it........because it works every time.
Every time now I see a post by Newbomb Turk, the needle on my BS meter shakes violently.....
I have had engines with 8.5:1 CR detonate on pump petrol.
There are many factors that can cause detonation, some are 'built in' to the original engine design which limits CR.
Far better to pick a modest CR & be safe; then you are not limiting your ign advance curve [ & losing power ] to try & control detonation.
Click to expand...

Or better yet, learn to build engines.

Just because you and that retard fire chicken or whatever he calls himself on speed talk can’t do something so it’s impossible.

More bad advice from a guy who spends more time surfing the web rather than really building something.

I can do it. It’s easy. Rule ONE is to put you on ignore. That’s the best start to building higher than orthodox compression ratios.
 
Are you referring to 'A ClassAct' on Speed Talk?

Oh yeah, every body is running 12:1 CR with iron heads on pump gas. I must have just missed them......
 
Well I’m looking to do the opposite in a sense. 1972 industrial 413 with dished pistons (unless I can find flat tops) and the 516 head. The piston edge is very close to top of the deck but not sure what compression I’ll have (steel shim head gasket)
 
Bewy said:
Yeah 12:1 on pump gas...& iron heads. Yeah right. That is why we are all doing it........because it works every time.
Every time now I see a post by Newbomb Turk, the needle on my BS meter shakes violently.....
I have had engines with 8.5:1 CR detonate on pump petrol.
There are many factors that can cause detonation, some are 'built in' to the original engine design which limits CR.
Far better to pick a modest CR & be safe; then you are not limiting your ign advance curve [ & losing power ] to try & control detonation.
Click to expand...
There's a guy over on The Hamb who runs on the street with 13.5:1 with iron heads on 93 octane. It's an Early Hemi, but he's got it done. I understand he drives it a LOT, too.
 
Bewy said:
Are you referring to 'A ClassAct' on Speed Talk?

Oh yeah, every body is running 12:1 CR with iron heads on pump gas. I must have just missed them......
Click to expand...

Nope. The guy on ST out of Canada that has Firebird or something like that in his user name.

Who knows, that could be your alter ego over there because that dude says you can't run more than 9.5:1 on pump gas.

That's wholly ignorant. Many of us who never bought the "pump gas limits compression ratio to 9:1" nonsense.

Go look up Ben Alameda on YouTube. He's another guy who builds high compression pump gas engines.

Then go look at Gold's Garage. A Canadian who builds high compression pump gas stuff too.

It's YOU who struggles with the simple stuff.
 
RustyRatRod said:
There's a guy over on The Hamb who runs on the street with 13.5:1 with iron heads on 93 octane. It's an Early Hemi, but he's got it done. I understand he drives it a LOT, too.
Click to expand...

LOL...there are so many guys building higher than orthodox compression ratios pump gas engines it's not funny.

Then you have certain people who will argue to the death it can't be done because THEY can't do it. Sad really.
 
Someone heard I had a virgin 426, a guy showed up with a roll of Ben
Franklin 's, I had to let it go
 
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