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Author Topic: Aluminum Heads  (Read 958 times)

Tom Dawson

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« Reply #15 on: September 12, 2009, 10:33:33 AM »

I have to disagree with Stan on this one-aluminium heads disperse heat faster-thus allowing you to run atleast one full commpression point higher than cast iron heads.
So you could get away with going to 10 or 11 to 1 where with the iron 9.5 would be the most you could use before detonation.
Tom
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Stan Paralikis

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« Reply #16 on: September 12, 2009, 01:41:27 PM »

Quote from: furyman67
I have to disagree with Stan on this one-aluminium heads disperse heat faster-thus allowing you...
Good point!

Dan Cluley

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« Reply #17 on: September 12, 2009, 11:32:03 PM »

Quote from: 1965Windsor361
Compression...
 
Fair enough.
 
In my case I see that as an advantage.  After switching to the 452's mine runs fine on mid grade gas saving a couple of bucks per tank.
 
I think it comes down to what sort of use you plan to get from the car.
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Jason Goldsack

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« Reply #18 on: September 13, 2009, 07:11:26 AM »

Well.... I'm not sure yet..

Now that my Big Block Aspen is gone :( I want a little more pep...

I think it's time to play a little. My buddy went 13.90's with his 1970 Fury with a 440 6 pack, 4.56 gears and 4000 converter.. I'm not looking for that.. but I would like to get in the low 15's .. the car has run 16.0 with 3.23 and a stock intake with the 452's

I'm going all around performance, maybe swap out the 383 magnum cam for something a little bigger, swap in some 3.55 gears, ported heads, swap bars front and rear, new springs in the rear.

I have gone 12's with the 452's on my 40 in my old Aspen.. so I do know they flow well ( but they were hogged out)

I'm just not sure what I want to do yet. I do know that the tranny will need a rebuild soon.. and that is top of my list.

I want to build an overall package that handles better but still has some pep. It would be a pain to find another BB with the bosses needed to fit my 1965 mounts.

I'm also looking for a winter project and porting the 516's sounds like it could keep me busy.



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Jason

(Eileen)1965 Chrysler Windsor, 361/727/2.76 16.49 @ 86 mph

Stitcherbob

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« Reply #19 on: September 13, 2009, 08:55:00 AM »


Quote from: 1965Windsor361
Well.... I'm not sure yet..

Now that my Big Block Aspen is gone :( I want a little more pep...





may I suggest you change your username to 1965Windsorstroker400,  Jason?

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Rich

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« Reply #20 on: September 13, 2009, 09:30:44 AM »

 I have been scrounging around in my old engine building books trying to remember why big port heads on a little engine don't work well (anyone remember the Ford Boss 302 with the huge port heads? It was useless on the street because it had no torque until 4,500 rpm)

 The best explanation I could find was in Andy Finkbeiners book "How to build max-performance mopar big blocks". He shows the "McFarland Formula" (RPM=cylinder head cross section area X 88200/Cylinder volume)  which basically gives the relationship between port cross section area and the RPM where the peak torque will occur. (McFarland was the head of R&D at Edelbrock)

 Using this formula, a 360 cubic inch engine with stock Mopar size ports will have a torque peak at 5,500RPM. With Max Wedge size ports that peak goes up to 6,900rpm. For comparison a 440 will peak at 4,600 with standard heads and 5,800 with Max Wedge heads. So what this means is, unless you want to make an all out drag racing engine that runs at ultra high rpm, you should leave the stock port size heads on it. Save the aluminum ones for the big 440's and strokers.
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Stan Paralikis

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« Reply #21 on: September 13, 2009, 12:55:52 PM »


Somebody FINALLY gets it.

Jason Goldsack

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« Reply #22 on: September 13, 2009, 01:50:18 PM »

But the 516 was stock on the 361.. they are the original heads..

I'm not talking about hogging them out.. just a nice port and bowl cleaning.. But gain back the compression i lost going to the open chamber head.

Maybe even using the MP templates.


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Jason

(Eileen)1965 Chrysler Windsor, 361/727/2.76 16.49 @ 86 mph

Leaburn Patey

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« Reply #23 on: September 13, 2009, 02:56:02 PM »

Just back cut the valves,open up the bowls a bit.
Simple and effective--especially on a set of 452's.
CBarge2009-09-13 19:56:57
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Jason Goldsack

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« Reply #24 on: September 13, 2009, 02:59:25 PM »


[/QUOTE]




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Jason

(Eileen)1965 Chrysler Windsor, 361/727/2.76 16.49 @ 86 mph

Rich

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« Reply #25 on: September 13, 2009, 06:05:27 PM »









The problem with the 516's , besides the small exhaust valves is the port roofs are low, the rest of the port is too curved, and the valve guide boss extends far into the port, and the intake charge stalls at high lifts because it can't make the tight curve where it opens into the seat. They don't flow all that well unless you spend crazy money having a pro port them for you.l

 346/452's offer a dramatic improvement in flow - the ports were flattened out and a "Huber" hump was added to the outside wall/floor creating a venturi effect that raises the velocity of the incoming mixture with no stalling at high valve lifts. This also mixes the incoming charge better reducing pollution (specifically the oxzides of nitrogen). Just adding a three angle valve job to a stock set of these will make them outflow hand ported 516's with big 2.14"/1.81" valves.  If you blend the bowls and add big valves you've got all the flow you'll ever need for a streetable  361-383.








krautmaster2009-09-14 18:46:49
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Snotty

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« Reply #26 on: September 14, 2009, 11:34:43 AM »

Does the above picture illustrate the difference between closed and open-chamber heads?  If so, I finally get that expression.
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Rich

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« Reply #27 on: September 14, 2009, 01:44:45 PM »

Yes it does!!

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Jason Goldsack

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« Reply #28 on: September 14, 2009, 03:11:33 PM »

it doesn't look like anything that my Dremel can't fix..

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Jason

(Eileen)1965 Chrysler Windsor, 361/727/2.76 16.49 @ 86 mph

Leaburn Patey

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« Reply #29 on: September 14, 2009, 03:58:32 PM »

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