How much should I mill off my intake?

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whit68

whit68

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G'day all

I have a new Edelbrock Performer intake on my 318 with J heads.

The bolt holes do not line up properly and are very difficult to torque down.

I am thinking I need to mill the manifold but I have no idea by how much. The heads etc were already on the block and I have no idea how much they were machined.

How can I work out how much I need to machine off the manifold?

Regards
Anthony
 
.............First set the intake on with no gaskets........do the bolts line up properly now...measure what u have for clearance .....is it the same side to side, front to back top to bottom.......report back.......pics would be great also.........kim.........
 
When I built my early Chrysler Hemi, I had the heads only milled .025". Hemi heads are a little different. Since the chamber is round at the head face, about the first .025-.030 removes a LOT of chamber volume relative to the amount milled, because you are milling the largest area of the chamber all the way around. So a little is a lot.

Little did I realize, the intake ports are at such a drastic angle to the heads, I had to remove about .063" from the intake face to realign the intake to the now milled heads. My machinist hated me, because he said that 1956 truck intake was some of the hardest cast iron he's ever seen.

Having said all that useless info, I am just trying to reiterate how important it is to make sure you get that alignment right. You will be forever chasing leaks of some kind if you don't.
 
I have the original manifold, is it possible to measure that one and then mill the new one?

Failing that I will measure it up next weekend and post what I find.

Thanks for the replys so far gents.

Regards
Anthony
 
Are theheads on the engine?

Measure the distance across the lifter valley from head to head.

Then measure the angle of each head.


Then compare to your intake and see how they stack up....
 
I had the same issue when I did my 273. The intake bolts barely lined up with no gasket but with the embossed steel shim gasket, no way. I think the shop took .010 off each side and it fit perfect. I know it wasn't much. They'll know how much. I bet they've run into this before many times. tmm
 
Milling Intake

There is no 'magic' number. You have to measure, or build a 'template' with
poster board.

Inexactitude is just a slightly-educated guess.
 
I just put on a performer intake. Nothing wanted to line up.
When I realized that the rocker covers were interfering, I took them off and the manifold aligned
 
If you find how much was taken off the heads there is a formula on how much to take of the intake port side of the heads so the intake will fit , instead of cutting the intake making it a one off for that engine or one with the same amount taken off the heads . Or maybe I had a few beers to many
 
~ Milling Formula ~

Mopar 340 & 360 Cylinder Heads

* To reduce Cylinder Head Combustion Chamber {By 1.0 CC} ............... Mill > .0048"

* For every .010" Removed from the Cylinder Head or Engine Block Deck.

* Amount to be removed from Intake Side {Manifold of Cylinder Head}.. Mill > .0095"

* The Cylinder Block Intake Rails {or Intake Manifold 'end-rails'} may also
require milling, to ensure a proper fit.
* For every .010" removed from the Cylinder Head or Engine Block Deck.
* Amount to be removed from the 'end-rails' ...................................... Mill > .0144"
 
69 Cuda 440 said:
~ Milling Formula ~

Mopar 340 & 360 Cylinder Heads

* To reduce Cylinder Head Combustion Chamber {By 1.0 CC} ............... Mill > .0048"

* For every .010" Removed from the Cylinder Head or Engine Block Deck.

* Amount to be removed from Intake Side {Manifold of Cylinder Head}.. Mill > .0144"

* The Cylinder Block Intake Rails {or Intake Manifold 'end-rails'} may also
require milling, to ensure a proper fit.
* For every .010" removed from the Cylinder Head or Engine Block Deck.
* Amount to be removed from the 'end-rails' ...................................... Mill > .0095"
Click to expand...

OR, if the angles are right, you could gasket match the ports, and elongate the bolt holes. the port alignment is important, as well as the angles being the same. of course how much the intake is off has a lot to do w/ the procedure of doing it this way or not. I have never had to mil an intake for any of my engines. also have not milled but one set of heads to raise compression, and that was a sbc, we took .068 off of them, and I still was able to make the intake work. "just my 2 cents"----bob
 
famous bob said:
OR, if the angles are right, you could gasket match the ports, and elongate the bolt holes. the port alignment is important, as well as the angles being the same. of course how much the intake is off has a lot to do w/ the procedure of doing it this way or not. I have never had to mil an intake for any of my engines. also have not milled but one set of heads to raise compression, and that was a sbc, we took .068 off of them, and I still was able to make the intake work. "just my 2 cents"----bob
Click to expand...

don`t forget to check the valve cover clearance too !!
 
69 Cuda 440 said:
~ Milling Formula ~

Mopar 340 & 360 Cylinder Heads

* To reduce Cylinder Head Combustion Chamber {By 1.0 CC} ............... Mill > .0048"

* For every .010" Removed from the Cylinder Head or Engine Block Deck.

* Amount to be removed from Intake Side {Manifold of Cylinder Head}.. Mill > .0144"

* The Cylinder Block Intake Rails {or Intake Manifold 'end-rails'} may also
require milling, to ensure a proper fit.
* For every .010" removed from the Cylinder Head or Engine Block Deck.
* Amount to be removed from the 'end-rails' ...................................... Mill > .0095"
Click to expand...

Your numbers are wrong for a small block Chrysler head. For every .010 milled from the block side of the head you mill .0095 from the intake side of the head or intake. From the Chrysler Racing manual and many years of experience.
 
66fs said:
Your numbers are wrong for a small block Chrysler head. For every .010 milled from the block side of the head you mill .0095 from the intake side of the head or intake. From the Chrysler Racing manual and many years of experience.
Click to expand...

My Error,

* Got the numbers 'reversed' for Cylinder Head {Intake Port Side} and Engine Block End-Rails.
 
69 Cuda 440 said:
~ Milling Formula ~

Mopar 340 & 360 Cylinder Heads

* To reduce Cylinder Head Combustion Chamber {By 1.0 CC}
Mill > .0048"
---------------------------------------------------------------------------------------
* For every .010" Removed from the Cylinder Head or Engine Block Deck.

* Amount to be removed from Intake Side {Manifold of Cylinder Head}
Mill > .0095"

* The Cylinder Block Intake Rails {or Intake Manifold 'end-rails'} may also
require milling, to ensure a proper fit.
* For every .010" removed from the Cylinder Head or Engine Block Deck.
* Amount to be removed from the 'end-rails'.
Mill > .0144"
Click to expand...

Double-Checked for correct milling amount.
 
One drawback of milling heads is that you will always have to have a milled intake to go with them whether it's the stock intake or a aftermarket intake installed later on.
 
toolmanmike said:
One drawback of milling heads is that you will always have to have a milled intake to go with them whether it's the stock intake or a aftermarket intake installed later on.
Click to expand...

Milling the intake side of the heads is always preferable to me since heads are usually a matched set. That way any intake will fit without modification.
 
66fs said:
Milling the intake side of the heads is always preferable to me since heads are usually a matched set. That way any intake will fit without modification.
Click to expand...

Yep!
 
famous bob said:
OR, if the angles are right, you could gasket match the ports, and elongate the bolt holes. the port alignment is important, as well as the angles being the same. of course how much the intake is off has a lot to do w/ the procedure of doing it this way or not. I have never had to mil an intake for any of my engines. also have not milled but one set of heads to raise compression, and that was a sbc, we took .068 off of them, and I still was able to make the intake work. "just my 2 cents"----bob
Click to expand...
YES , just cut 0.060 off my ede heads didn't touch the intake . Guess I had just enough beer
 
oldkimmer said:
.............First set the intake on with no gaskets........do the bolts line up properly now...measure what u have for clearance .....is it the same side to side, front to back top to bottom.......report back.......pics would be great also.........kim.........
Click to expand...

Whit, did you read Kim's post? This is the method I use and will tell you a bunch
 
fishy68 said:
Whit, did you read Kim's post? This is the method I use and will tell you a bunch
Click to expand...

Yep will do this over the weekend and report back with what I find and pics.

Thanks everyone I appreciate the input.

Anthony
 
whit68 said:
Yep will do this over the weekend and report back with what I find and pics.

Thanks everyone I appreciate the input.

Anthony
Click to expand...

would also rather mill the intake surface of the heads if it comes to that .
 
OK i have sat the manifold on without gaskets and the threads on the heads are pretty much centred with the holes in the head and the same both sides.






The angle between the block and heads matches the new manifold, I have also compared the old manifold the the new one and again the angles are the same.

You can see below that the port alignment was pretty good from when I installed it the first time.






Do you think it is OK to elongate the holes on the manifold?

cheers
Anthony
 
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