I'm too lazy to search the internet for you today. I did one a while back and came up with a site that had tables specifying how much and what angle you'd have to mill the intake for x amount of head mill. I don't know if you'd have too big a mismatch to require further milling, at .030, I doubt you'll need to take any further action.

I'm betting a lot of people get their heads milled and compensate with thicker gaskets or something similar instead of getting their intake milled. Bet it wouldn't be more than $75.

 

cool... all i needed to know really.

nice 00 v6 conversion... sounds sweet. I know the work involved as I almost did it.

 

Almost? What happened?

 

No more then likely you won't need to mill the intake. I did not have to and she ran just fine with no problems.

 

I wouldn't take a chance with it because the challenges it CAN cause are pretty big. I'd take the heads and intake to a competent machine shop and let them mock it up. They can tell you if anything needs to be done to the manifold - sometimes nothing at all; sometimes just a clean up/port match; sometimes milling the bottom of the intake; sometimes 'ovaling' out the holes of the intake so the bolt holes in the head still line up. When the head is cut, the heads not only sit slightly lower, they also sit slightly closer together which moves the threaded holes in the heads that the manifold bolts must line up with.

Also, with the heads cut, the pedestals are sitting lower - which means you'll likely either need to shim the rockers up or use shorter pushrods. Also, whatever p to v clearance you would've had is reduced by .030" - so if there's any doubt at all, p to v needs to be checked.

Like I said - there are lots of POTENTIAL implications. Probably ought to check this stuff out rather than just assembling. When it comes to these kinds of fine dimensional changes, what happened on someone else's motor really isn't predictive of what's gonna happen on yours.

 

Milling

Generally speaking, you are safe not to mill with .025 off the heads. .005 isn't much more. Why not drop the intake down on the longblock and see how it looks. You will see a gap at he front and back of the block between the intake and block. If a gasket and a big bead of RTV won't seal it, then for .030, you need to ~.015 milled off the intake. I took my GT40's down .025 and was fine without mililng the intake, just took a big dab of RTV. Good luck.

 

cool, thanks everyone.

Alienninja - what kind of power are you making with your combo? Sounds like its going to be pretty darn close to my setup.

 

Never got to put her on the dyno, she ran 8.5's at 82mph off 2.0 60's, that was with stock intake, lower was touched up but not ported much. Last week she blow up, due to a few things mainly dropping a valve and taking out one of my beautiful heads . So I am in the process of rebuilding her.

 

OUCH....

sorry to hear.

 

erick,

to avoid all the problems that these others have had,

you have to pull it out,

look at the front to rear alignment and angle of the alignment of the gaskets .

this cannot be done accurately with the engine in the car....
because there is no way to see the back-rear of the block.....

and it is just as difficult to do any pushrod / rockerarm checks with the engine in the car...


do it now,

or you will do it later,

just like the crank oil seal problems.

 

I dont know have a clue what Im talking about here so help me out.

I bought some gt40p heads that were milled .030

then I heard I need to mill my intake.

anyone?

who does milling of intakes? cost?

thanks!

I milled mine .030 -no problems. Had to shim rockers though. Check p-v clearance with clay.

 

doh!

You mean I need to pull the engine to install heads? Ive NEVER heard that one B4.

 

your original question was to know if the bolt holes or gasket areas would match up...

well, there is no way to know without looking.

you have to pull the engine to be able to see the rear of the heads and block.

there is no way to see if the angle of the two heads and the manifold match...

you cannot see in there because the firewall and the W H O L E CAR is in the way.

but you can see the front......

anyways, when you do the rocker-valvetrain check for geometry and pushrod check,

and then do the piston to valve checks,

it is a lot easier when the engine is out of the car.....

 

and when it is found to be off or the angle is incorrect, there is no accurate way to know how much material to machine off to be able to match the manifold, head and the block ...TOGETHER....if you do not mock it up with the exact....EXACT block that it will be bolted on to.

 

I had my GT40P heads milled .030 and i didnt mill my intake. Ive had no problems.

 

Thanks for the info Kato. Im not trying to be argumentative, Im just trying to understand fully. I appreciate your info and help on this subject.

thanks!!

 

What Kato's pointing to I tried to touch on in my first post. One person's experience with what happened when they cut their manifold is simply not applicable to another manifold/head/block. WHen it comes to dimensions in hundredths and thousandths, just like with p to v clearance, each set up is unique. Each person has to look at theirs to determine if it's gonna work without cutting the intake, or ovaling holes, or changing pushrod length, or shimming pedestal rockers, or port matching to clean up mismatches, etc.

Also know, there are plenty of combos out there where the poster says "it worked on mine, didn't cut the intake", and what they don't know is that they've got a .020" or .030" port mismatch or bad rocker geometry that's putting side loads on the valves harming guides -- because they didn't know enough about the geometry and implications of cutting the heads to check any of those things.

It's probably the biggest single unintentional (sometimes intentional) potential error made on forums like this. People ask "can I do this?" And others answer "I did - so you can", or simply "I did", the asker assumes they can to. More often than not, just because it worked on someone else's engine/tranny/rear end, doesn't mean it will work on yours.

 

thanks Micheal.

the idea of pulling the engine scares me... but, ya gotta do....

 

I thank mikey again....


I have seen quite a few that match up pretty good .....by luck,

but the bolts have been JAMMED into the H OLES.....and threads begin to get stripped out....

and then when the engine heats up,...the manifold leaks at the gaskets....

......instant lean-out.....

....occasional rough running...... stumble....stumble....

...a couple of cylinders that begin to smoke....

...and the occasional cracked manifold.....




...........when you dont look,

....you just dont know.....



I guess the way most people solve the problem is by using a CAULKING GUN FULL OF SILICONE........

 

I can't agree more with Kato and Mike. Many guys will do it and the manifold will bolt on fine. But with a stock or even a GT40/cobra intake you can't see down the ports good enough to see the .020-.030 misalignment at the ports. This KILLS your power and can cause all kinds of trouble as Kato described. I don't think you have to pull the motor though to check it, I believe a good machine shop can mock it up for you and get it pretty darn close. But the most accurate way is to set it all up on YOUR motor and check it. I am in the same delimma, we plan to pull my GT40P heads off soon and I am milling them to get around 54-55cc chambers (way more than .030 mill!) so I am going to have to have the manifold done too.

 

sskiller - don't forget the bolt holes and your pushrod length/rocker height...not to mention p to v....

 

Got it Mike, I have a DSS bottom end with forged pistons and plenty of relief so I think I will be fine with P to V clearance. I have the whole shim kit for my rockers so I should have no problems setting up the rocker geometry, and a long cold winter so plenty of time to get it right!

 

take this to the top

 

The angle of the intake bolts in the small V-8 ford causes a lot of "lift"on the cylinder heads if the intake is a little "wide".
Most other engines have intake bolts that are perpendicular to the manifold surface.
The ford intake bolts thread straight down into the head.
It is quite possible to compromise the head gaskets because the torque needed to force the intake to seal is reducing the clamping force of the head gaskets. (when the intake needs milling)


If you have head gasket problems...
Look for signs of combustion tracks across the deck above all the cylinders.
The engine may even hold a leak down test, but still leak when hot under running conditions.
I have decked the block as little as .015", and milled about the same off the heads and run into problems. But you never know for sure how much the heads may have been milled before.

You need to check!

 

....YUP.....