Cylinder head questions

1968rt · May 30, 2019

I have a set of small exhaust 915s. They are clean and havent been run. You would need to install your 1.74 exhaust valve. $400, but shipping will kill you

khryslerkid · May 30, 2019

1968rt said:
Milled these over .070 to 67 ccs. Been over 7 years no problemsView attachment 774809 View attachment 774810 View attachment 774819

And what did you do on the intake side. What mods did you have to do to the valve train if any.

Here's my specs useing 452 untouched heads. TRW flat tops, .040 over .050 in the hole.

BSB67 · May 30, 2019

69greenleaf said:
.......... Or maybe just fork up the cash for some close chamber aluminum heads.

This, but I'm not a professional. To make either the 452, or 915 equal the power increase you'll get with aftermarket aluminum will cost you more than the aluminum.

1968rt · May 30, 2019

I did mill the face, but I cheated a little. Milled the intake a bit also.

khryslerkid · May 30, 2019

1968rt said:
I did mill the face, but I cheated a little. Milled the intake a bit also.

Trying to get the open chambered heads to 10.1 takes a bit. Just to run them on the street with todays gas just touch them up and run the lower compression with a mild cam.

If you're racing, go closed chambered or higher compression pistons. You see my specs that I posted...there's no quench. That's another factor you have to consider. My "budget build" is very street friendly, runs great, 165 average compression and can smoke the tires. That's all I need.

68Moparmaniac · May 31, 2019

The amount of money your going to drop on modifying those open chamber heads will cost more than for a set of new closed chamber aluminums. I have over $2500 worth of port work, guides, valves, springs and seals in my 915's.
These new heads are ranging from $700-1800 for bare or built heads or you can go the extra mile and pick up the below package and call it done for now until you're ready to build that stroker you want.

Edelbrock 2087 - Edelbrock Total Power Package 482 HP 440 Big Block Chrysler Top-End Engine Kits

Compare

Top End Engine Kit, Power Package, Intake, Heads, Cam, Timing Chain, Head Bolts, 440 Chrysler, 482HP, Kit

Part Number: EDL-2087
$2,404.95

Cranky · May 31, 2019

69Bee said:
Rule of thumb for BB Mopar heads (79/81/83cc heads), remove 0.0042" per 1cc of volume. Therefore, 10cc would equate roughly to 0.042". I agree with uneven chamber volumes, and that they are actually where they say they should be. Measure to verify your numbers and do the math. The main thing to remember here is that IF you decide to work the 452 heads, they WILL need guides/ex seats/ valves/ springs, and deck milling (obviously), but do NOT cut the intake, mill the intake side of the head instead. If you mill the intake, it is now married to that engine. Mill the heads, and the intake can be used on any engine. The intake side of the head should be milled 0.0123" for each 0.010" milled from the head/block. This means that if you mill only the head (not block deck) 0.042", you would need to remove 0.0492" from each intake side of the head. Since the manifold doesn't seal to the block, it isn't necessary to mill the valley rails, but I do to clean them up and for head/valley alignment. I usually cut about 0.012" to 0.015" for a general head/block cleanup, but you would need to cut a little more for 0.042" head cut.

Keep in mind that the numbers for cutting is a rule of thumb deal. I've found some intakes that actually fit better after milling the heads .030" and I know the intakes I had on hand at the time were factory originals. Always need to do a mock up before machining....

1968rt said:
Milled these over .070 to 67 ccs. Been over 7 years no problemsView attachment 774809 View attachment 774810 View attachment 774819

Milled a open chambered head .100" once....turned it into a closed chambered head lol. Gotta make sure core shift is in your favor though before doing something like that. My case, it wasn't.

khryslerkid said:
And what did you do on the intake side. What mods did you have to do to the valve train if any.

Here's my specs useing 452 untouched heads. TRW flat tops, .040 over .050 in the hole.
View attachment 774840 View attachment 774841

Closed chambered heads on a .050 down stock bore 440 using steel shim gaskets produced 10.3-1.....

biomedtechguy · May 31, 2019

69greenleaf said:
Just got off the phone with my local machine shop. It’s looking that the cheapest route will be to mill the 452’s I have down. Does anyone have an idea how much I can safely take out to not have to do any major modifications? The machinist I talked to say it would probably be around .040 to get them down to 80cc. Does that seem right/safe to do?

Trick Flow 240s

IQ52 · May 31, 2019

Performance and dollar wise, running a factory iron head in a race application is a dumb idea...........unless you are required to do so by the rules.

This is from experience as we are the guys who can, normally aspirated on 91 octane, make well over 700 HP with our ported 906 factory iron.

69Bee · May 31, 2019

Cranky said:
Keep in mind that the numbers for cutting is a rule of thumb deal. I've found some intakes that actually fit better after milling the heads .030" and I know the intakes I had on hand at the time were factory originals. Always need to do a mock up before machining....

Milled a open chambered head .100" once....turned it into a closed chambered head lol. Gotta make sure core shift is in your favor though before doing something like that. My case, it wasn't.

Closed chambered heads on a .050 down stock bore 440 using steel shim gaskets produced 10.3-1.....

True, as I said, rule of thumb. At least you know the target, and there might be a little adjustment necessary on assembly. When I mill the intake side of the head, I use a BHJ alignment fixture to ensure the head angle is correct for the intake, and it is usually off a little.

Cranky · May 31, 2019

69Bee said:
True, as I said, rule of thumb. At least you know the target, and there might be a little adjustment necessary on assembly. When I mill the intake side of the head, I use a BHJ alignment fixture to ensure the head angle is correct for the intake, and it is usually off a little.

View attachment 775113

You sure did say rule of thumb.....looks like I didn't hear it

Challenger340 · Jun 1, 2019

69greenleaf said:
I have a 68 model 440 block and rotating assembly (Not the 6-pack setup) with a set of “untouched” 452 heads. From what I have been reading online measure out to 88-90cc,putting my motor between 8.6:1 and 9.0:1 . I’m wanting to get my compression ratio around 10:1 maybe even 10:25:1. I am wanting to get the head cc down to 75-80cc. Would I be able to mill the 452’s down that much and still have my intake manifold fit properly? Would it be better to spend the money on some close chamber 915’s? Or maybe just fork up the cash for some close chamber aluminum heads. Just wanting some professional advice before I make my next move. Thanks.

IMO, For best results ?
don't "assume" anything while in the planning stage, especially around Compression Ratio increases !

For example here, you said: (don’t know exactly how far the piston are in the hole)
Get a Head OFF the Engine and CC it.... and MEASURE how Far the Piston is down the hole FIRST !

Cranky · Jun 1, 2019

Challenger340 said:
IMO, For best results ?
don't "assume" anything while in the planning stage, especially around Compression Ratio increases !

For example here, you said: (don’t know exactly how far the piston are in the hole)
Get a Head OFF the Engine and CC it.... and MEASURE how Far the Piston is down the hole FIRST !

Yup....nlot easy to tell what's in an engine that's over 50 years old. Once inside is when you will know if someone has had their hands in it but that can sometimes be hard to tell too.

dvw · Jun 3, 2019

10-1 isn't going to like pump gas with the stock cam.
Doug

wyrmrider · Jun 4, 2019

true 10 :1 stock chambers iron heads is tough even with kb pop up pistons with even stock HP cam
you have to rev it past peak torque to prevent detonation can do it when racing
with al heads and tight quench you still have to stay away from full throttle mid range long pulls

Cylinder head questions

1968rt

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khryslerkid

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BSB67

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1968rt

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khryslerkid

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68Moparmaniac

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Cranky

Banned Henchman #27

biomedtechguy

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IQ52

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69Bee

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Cranky

Banned Henchman #27

Challenger340

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Cranky

Banned Henchman #27

dvw

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wyrmrider

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