Intake port alignment milling question

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wyrmrider
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Re: Intake port alignment milling question

Post by wyrmrider »

Direct connection book verifies previous poster
for each .010 off the heads or block cut the manifold or head face .0123
Min head CC 79.5 which is usually called 80cc and for the 67 915 73.5cc usually called 74cc
6 "pack deck" clearance minimum
69 79.5 cc .027
70-71 79.5 .001
440 4bbl
66-67 73.5 cc .059 down
68-69 79.5cc .027 down
70-71 79.5cc ..051 down
72-73 81.95cc .123 down
74-75 83.1 cc .123 down
76-78 81.5 cc .113 down

something funny with these numbers as 6 pack piston was same compression ht AFIK at 2 1/16
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Re: Intake port alignment milling question

Post by no green »

I talked to Edelbrock tech, and he said that head and that manifold is made for a stock deck height, stock thickness head gasket, and single layer intake gasket (not valley pan)... so if we take .005 off the head, .005 off the deck, have .027" head gasket, and .065 intake gaskets... so we're off .075"-.080" off out of the gate. Account for tolerance stack up, and .100" sounds realistic, now.

That intake didn't fit our old motor very well, when we removed it, we noticed the bottom of the flanges weren't hitting the intake faces of the heads right.

I'm going to pick up a new manifold after work today, just to see if a fresh one fits any better. If it's just as bad, we'll return it and start sawing on the one we have.

I understand about the intake faces (head vs. intake), my machinist said to cut it off the head, but after dad and I weighed the options and what fits our needs and timeline, we think we're going to take it off the intake manifold.
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Re: Intake port alignment milling question

Post by no green »

wyrmrider wrote:Direct connection book verifies previous poster
for each .010 off the heads or block cut the manifold or head face .0123
Min head CC 79.5 which is usually called 80cc and for the 67 915 73.5cc usually called 74cc
6 "pack deck" clearance minimum
69 79.5 cc .027
70-71 79.5 .001
440 4bbl
66-67 73.5 cc .059 down
68-69 79.5cc .027 down
70-71 79.5cc ..051 down
72-73 81.95cc .123 down
74-75 83.1 cc .123 down
76-78 81.5 cc .113 down

something funny with these numbers as 6 pack piston was same compression ht AFIK at 2 1/16
I think I have that same DC book your referring to, I built the old 440 from it. I forgot I had it, I'll have to dig it out.

Thanks for the info.
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Re: Intake port alignment milling question

Post by wyrmrider »

I have a pretty good collection from the early 70's mostly worn out
remember that those cc's are NHRA minimums but also are what the factory based the advertised compression ratios on
in reality I've seen the late smog heads close to 90 CC
the closed chamber heads may be 80 cc and the 906 more like 85 cc
also end to end can change so any head mill requires cc ing all four end chambers then milling to match smallest and then go from there
don't do much chamber mod or valve relieving till you equalize the two end chambers then balance with grinding in the individual chambers
5 cc of metal removal in the chamber is a lot
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Re: Intake port alignment milling question

Post by amc fan »

AMC are right angle also! Port layout is the same as 383/440 we cut 383 intakes and weld amc flanges on.If you are cutting the flange surfaces I insert feeler gauges to make sure I get the fit as good as I can.sometimes they are off 7-10 thousandths on a side and you can straighten it out when you are cutting it to get it dead nuts on!
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Re: Intake port alignment milling question

Post by wyrmrider »

OTB intake flanges are frequently off for BBM they do not "get" the funny angle
you do not want air leaks at the bottom
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Re: Intake port alignment milling question

Post by speedmachine »

If I understand it correctly, you are using a tin valley pan gasket sandwiched in between 2 paper gaskets??? That would likely be the problem. I use the valley tin alone or one set of paper gaskets with a lifter valley cover. If you stack them the intake is not going to fit. You would have to mil the intake face of the head to make it work.
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Re: Intake port alignment milling question

Post by wyrmrider »

paper on each side of the bathtub is what MOPAR has called for
try the bathtub alone with hylomar just around the ports
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Re: Intake port alignment milling question

Post by speedmachine »

All the factory BB mopars I have ever seen use a tin valley gasket with sealer.
The paper gaskets were used for aftermarket pieces that had a cover over the lifters
Like the Indy style heads with the aluminum lifter cover. I never heard of mopar suggesting that you use
Paper in conjunction with the tin valley pan gasket. I am not saying you are wrong, just in all the years
Of building mopars I have not heard this.
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Re: Intake port alignment milling question

Post by af2 »

speedmachine wrote:All the factory BB mopars I have ever seen use a tin valley gasket with sealer.
The paper gaskets were used for aftermarket pieces that had a cover over the lifters
Like the Indy style heads with the aluminum lifter cover. I never heard of mopar suggesting that you use
Paper in conjunction with the tin valley pan gasket. I am not saying you are wrong, just in all the years
Of building mopars I have not heard this.
If I remember the pan had a bead around the ports to seal. I have never seen paper either when running the valley pan.
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Re: Intake port alignment milling question

Post by wyrmrider »

I'd better check the book later today
I usually ran valley pans with no paper for the alignment issue
but I've had motors come into the shop with both
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Re: Intake port alignment milling question

Post by no green »

Follow up in case someone else has the issue.

We took the bathtub valley pan back and got one of these: http://store.440source.com/Sheet-Metal- ... /127-1009/

Using a single layer intake gasket, and .040" head gasket (had too much quench with the .027), I calculated we needed to take .080" off the flanges to make them fit... so I had the machine shop mill that much off, and the intake fits like a glove, now. The ports are only going to need a slight clean up, and are pretty well matched all around.

Thanks for the help, guys.
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