Deck height question
 

Just mocked up my rotating assembly for my 461 and im .025 in the hole. I want to zero deck to end up with just under 11 to 1 compression ratio. Will I end up with any intake mounting issues milling that much off the block? I'm using highport heads with a northwind intake.

Possibly. You'll be creating a narrower "V", so depending on the accuracy of the intake machining it may need milled also.

X2 More likely than not. Assume that that step will be required.
What gasket are you assuming?

Tom V.

Is this more then normal as far as the amount I'm looking to take off the deck?

why Don’t you mock it all up with The heads just sitting on the block with head gaskets and with the intake just sitting on the gaskets .
If you can get all the intake bolts started without much of a fight then I would get the intake flange on each head milled the same .025” as the block, or at least .015”.

No this amount is not more then normal, as the stock deck hight is stated by the factory to be .023” for the 455.

Stock and super stock racers fighting for every Crumb of compression would cut the deck .100” to get rid of most of the valve notch chamfer at the top of each bore., so a mill of .025” is nothing!

What calculator are you using to determine your compression ratio?

Tom V.

Gaskets are .045 crushed thickness butler branded. I used Butlers compression calculator, my machine shop mocked it up today and the deepest piston was .028 with the tallest being .025. I was going to have him mill the .025. I called Ross for the cc of the dish on the piston as these were custom ordered from butler.

I just squared-up and zero decked a 1968 400 block last week. .007" deck height difference side to side before I began and I ended up removing .018 and .025" to get it all fixed up. That was pretty bad for a Pontiac block. Mexican SBC's are the worst I deal with. Typically vary front to rear .010'.012". Take .025-.030 to square up. Intakes often need to be cut and end seals on the intake manifolds can't be used. Have to just seal with RTV.

Good Advice there.

Tom V.

Sounds good, I don't mind getting the intake milled just wanted to be sure that the amount needing to be milled didn't seem to accesive.

Many years ago we took an original 1970 2-bolt block and had it squared to within 0.002" corner-to-corner variation and decked to within minimum 0.002", at least according to the paperwork.
The deck height ended up at 10.215".


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If you need to get something milled then why moll the Intakevas that will Marry it to that build!

If you mill the intake face of the heads then that manifold can be used on other motors and also more easily be sold.

Don't really want to mill the brand new highports in case I use them on another block, rather mill the intake face it's much cheaper to replace. Not only that but I would probably have to disassemble the heads and clean them up afterwards.

I had my 400 block decked .025 to achieve zero deck. I had no problems mounting either a T2 or stock intake. KRE heads.

I always disagree with Ross on their stated piston dish size. It's not much but always a little larger than what they say. Last set I requested 25cc, their sheet said 23.8cc and actual was 25.2cc's.

I usually go with milling intake side of the heads like Steve said, but you have a good point on leaving the High-Ports alone. And yes you do have to strip the heads all the way down including removing the valve stem seals.

Just because you can get bolts started doesn't mean that things are good. If your intake ports were properly aligned and port matched, then taking .025" off either the deck or head surface means that the intake manifold port is now sitting .025" above the head port. Not the end of the world, but it is off.

Or look at a thinner head gasket. Cometics has them starting at 0.018 so total quench 0.043.

most would typically hack the intake down .....because who really cares? ..it's an INTAKE MANIFOLD....$300 you can buy another.....worst case..(if you MUST sell it or another build).you double up INTAKE mainfold gaskets...again so what? cheap easy move on...

SCE even makes double thick intake gaskets. I cut the intake as even many out of the box need milling to fit-my machinist says all brands he has to cut to fit. The one T2 I have on my current 455 was used and one side was already too short do it takes a double gasket the side a single thickness.

V8 Intake Surface Mill Calculator

http://www.wallaceracing.com/calc-intake-mill.php


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You could mill less than the total amount and combine with a slightly thinner gasket. Going to a much thinner gasket could be an issue. The thinner gaskets I've see require a more perfect finish from what I have read. I think you may be fine with even an 025 mill as far as intake lining up, I have milled more from heads before they didn't line up, but each build may be different, and I imagine the intakes come from the factory with slight variations. I may have just been lucky with my intake/head combo.